hfrr service manual 02032011

7/21/2019 HFRR Service Manual 02032011

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PCS INSTRUMENTS

Fuels and Lubricants Test Equipment

HFRRService Manual

Version

1



HFRR Service Manual

PCS Instruments78 Stanley Gardens • Acton

LONDON W3 7SZ, UKPhone +44 (0)20 8600 9920 • Fax +44 (0)20 8600 9921

[email protected]



COPYRIGHT NOTICE

The Copyright in this work is vested in PCS Limited. The document is issued in confidence solelyfor the purpose for which it is supplied. Reproduction in whole or in part or for use for tendering or

manufacturing purposes is prohibited except under agreement with or with the written consent ofPCS Limited and then only on the condition that this notice is included in any such reproduction.

IMPORTANT NOTICE

This manual is primarily intended for use by authorised PCS service agents. In the event of aproblem, end users should consult either their local distributor or PCS Instruments directly. Attempting to repair or service a unit may invalidate the instrument’s warranty.



Table of Contents

COPYRIGHT NOTICE............................................................................................................................................ I

IMPORTANT NOTICE .......................................................................................................................................... I

1.0 CONTROL UNIT ....................................................................................................................................... 1 1.1 PCB LAYOUT ................................................................................................................................................. 1

1.1.1 Test Points ...................................................................................................................................... 5 1.1.2 Adjusting the HFRR control unit ................................................................................................... 5

1.2 MULTIWAY/QM SOCKET ............................................................................................................................... 6 1.3 RTD SOCKET .................................................................................................................................................. 7 1.4 PC SOCKET .................................................................................................................................................... 8

1.4.1 PC Configuration - PCB Issue 1 & 2 .............................................................................................. 8 1.4.2 PC Configuration - PCB Issue 3 ..................................................................................................... 9

1.5 TEMPERATURE AND HUMIDITY SENSOR ........................................................................................................... 10 1.6 POWERSUPPLY ............................................................................................................................................ 11 1.7 POWERAMPLIFIER ....................................................................................................................................... 13

1.7.1 Measuring the amplifier ............................................................................................................. 15 1.7.2 Replacing the amplifier ............................................................................................................... 17

1.8 FANASSEMBLY ............................................................................................................................................. 19 1.8.1 Testing the fan ............................................................................................................................. 20 1.8.2 Replacing the fan ......................................................................................................................... 20

1.9 CHANGING THEFLASH MEMORY CHIP ............................................................................................................. 22

2.0 MECHANICAL UNIT ............................................................................................................................. 26

2.1 MULTIWAY SOCKET....................................................................................................................................... 27 2.2 MAIN/ALARMRTD ANDRTD PROBE SOCKET................................................................................................. 28

2.2.1 Testing the Main RTD Probe ...................................................................................................... 29 Testing the Alarm RTD .................................................................................................................................. 29

2.2.2 Testing the Alarm RTD ................................................................................................................ 30 2.2.3 Replacing the Alarm RTD ............................................................................................................ 31

2.3 VIBRATOR .................................................................................................................................................... 34 2.3.1 Testing the Vibrator..................................................................................................................... 34

2.4 LVDT .......................................................................................................................................................... 35 2.4.1 Testing the LVDT .......................................................................................................................... 36 2.4.2 Testing the LVDT offset – PCB test point ................................................................................... 37 2.4.3 Adjusting the LVDT offset ........................................................................................................... 37

2.5 HEATER BLOCK& HEATERS ............................................................................................................................ 38 2.5.1 Testing Heaters ............................................................................................................................ 38 2.5.2 Replacing Heaters ....................................................................................................................... 39 2.5.3 Replacing the heater block ......................................................................................................... 42

2.6 FORCETRANSDUCER ..................................................................................................................................... 45 2.6.1 Testing the force transducer ...................................................................................................... 45 2.7 THEFRETTINGFLEXURELOCK ........................................................................................................................ 49

2.7.1 Testing the microswitch .............................................................................................................. 50 2.8 ECR (ELECTRONICCONTACT RESISTANCE) ...................................................................................................... 51

2.8.1 Measuring the ECR voltage from the mechanical unit ........................................................... 51 2.8.2 Testing the ECR connections ...................................................................................................... 52 2.8.3 Measuring the ECR voltage from the PCB ................................................................................ 52

2.9 MEASURING THE FREQUENCY ........................................................................................................................ 54 2.10 REPLACING THEPUSHRODINSERT ........................................................................................................... 55

3.0 ACCESSORIES ....................................................................................................................................... 59

3.1 HFRR MICROSCOPE ANDMICROMETER ........................................................................................................ 59



3.1.1 Fitting the Micrometer to an HFRR Microscope Ball Stage .................................................... 59 3.2 HUMIDITYCABINET....................................................................................................................................... 61

3.2.1 Testing the Heaters ..................................................................................................................... 61 3.2.2 Testing the Temperature Sensor ............................................................................................... 62

3.2.3 Testing the temperature control dial ........................................................................................ 63 3.2.4 Replacing the Fan ........................................................................................................................ 64

4.0 TROUBLESHOOTING ........................................................................................................................... 66

4.1 HFRR CONTROL UNIT ERROR MESSAGES ........................................................................................................ 66 4.2 GENERAL TROUBLESHOOTING PROBLEMS ........................................................................................................ 68

4.2.1 Wear scar outside standard ....................................................................................................... 68 4.2.2 Incorrect stroke length ................................................................................................................ 68 4.2.3 No Film/ECR and heaters unstable ........................................................................................... 68 4.2.4 No connection to PC - PC software does not recognise instrument ...................................... 68 4.2.5 HFRPC software shuts down while a running a test ............................................................... 69 4.2.6 PC software displays “the instruments date and time is different from the computer date

and time” every time the software is loaded. ............................................................................................ 70 4.2.7 Status bar displays “Main RTD Not connected” ...................................................................... 70 4.2.8 RTD Error message appears only when starting test .............................................................. 70 4.2.9 Cannot calibrate Force Transducer because pushrod keeps on running .............................. 70 4.2.10 Control unit case becomes hot................................................................................................... 70 4.2.11 PC software error messages ...................................................................................................... 70



1

1.0 Control Unit

Servicing the HFRR Control Unit

1.1 PCB Layout

PCB layout for Issues 1 and 2

Chapter

1

Pin 1

POT 1

Flash MemoryChip

Multiway/QMCable Socket

RTD CableSocket

Humidity & Temperatureprobe socket

Power Amplifier

Power SupplyLVDT Test PointP51

Force Transducer

Test Point P52

POT 4

ECR Test PointP53

Analogue and DigitalGround P20

Keypad RibbonCable

Gain control to power amplifierPOT 2

Test Point P50

PC Serial Connection

CPU

LCD Display



2

PCB layout for Issue 3

Analogue and DigitalGround P20

LVDT Test Point P51

LVDT offset adjustmentPOT 4 Force Transducer Test Point P52

ECR Test Point P53

Gain control to power amplifierPOT 2

KeypadFlash MemoryChip

Test PointP50

POT 1

LCD

PC SerialConnection

CPU



3

PCB Connector Layout for Issue 1 and 2



4

PCB Connector Layout for Issue 3



5

1.1.1 Test Points

Test Point Description Output (approximate)

P50 O/P Frequency 50Hz Sinewave,1.22Vp/p when running test @1mm stroke lengthOr Approx 417.7 mV AC @1mm stroke length

P51 LVDT Offset 2.29V (DC) when idle

P52 Force Transducer[see HFRR mechanical unitforce transducer for moreinformation]

2.5V (DC) when idleMaximum O/P whenapplied pressure: 5V (dc)

P53 ECR 3.8V (DC)

P30 PCS Use Only N/A

P20 Analogue and Digital GND N/A

1.1.2 Adjusting the HFRR control unit

Pot Adjustment Description Test Point Notes

POT 1 LCD Contrast N/A Adjusts contrast ofLCD on control unit

POT 2 O/P Frequency P50 Consult PCS beforeadjusting

POT 4 LVDT Offset P51 Adjusts offset of theLVDT position



6

1.2 Multiway/QM Socket

Note. Issue 1 PCB’s do not have the ‘Cable Select’ function. Some early versions of Issue 2 PCB’salso may not have the ‘Cable Select’ function.

Function Colour From QM Pin To PCB (pin)

Heater1 Red A P17 (1)

Heater1A Blue B P17 (2)

Heater2 Green C P17 (1)Heater2A Yellow D P17 (2)

Microswitch 0V White E P7 (2)

Microswitch Black F P7 (1)

LVDT Primary + Brown G P23 (1)

LVDT Primary - Violet H P23 (2)

LVDT Secondary + Orange J P23 (4)

LVDT Secondary - Pink K P23 (3)

Force Transducer + TRQ L P18 (1)

Force Transducer - Grey M P18 (2)

Vibrator + Red/Blue N Power Amp O/PVibrator - Green/Red P Power Amp 0V

ECR + Yellow/Red R P16 (1)

ECR - White/Red S P16 (2)

Cable Select 1 Red/Brown T P8 (1)

Cable Select 2 Red/Black U P8 (2)

Screen n/a W, X, Y, Z Tray chassis

AB

L

C

D

E

F

G

HJ

K

R

M

N

P

Z

S

T

U

V

W

X

Y

External view of multiway socket on the HFRR control unit



7

1.3 RTD Socket

From 9-waySocket

Function Colour To PCB (3-way orangeconnecter)

1 Main RTD 1 Red P14 (A)

2 Main RTD 1A Blue P14 (C) links to pin 1 (C)

3 Alarm RTD 1 Green P15 (A)

4 Alarm RTD 1A Yellow P15 (C) links to pin 1 (C)

1 2 3

C C A

Example of 3-pin

connection to PCB

Main RTD (P14)

Alarm RTD (P15)

5 4 3 2 1

9 8 67

External view of 9-way socket on the HFRRcontrol unit



8

1.4 PC Socket

The serial connection (also referred to as RS232) uses a 3-way screened signal cable. The screenof the cable is connected to chassis. The RS232 connection to the PCB varies in different issuesof PCB. The Issue number is printed on the PCB close to power supply.

Function Colour From 9-waySerial Socket

To PCB (pin)

RX Red 3 1

TX Black 2 2

GND White 5 3

1.4.1 PC Configuration - PCB Issue 1 & 2

The 3-way cable inside the control unit is connected to a 3-pin header located on P4 of the PCB.The jumper setting is located on P6 of the PCB (issue 1 & 2 only) and is factory set tocommunicate using the RS232 protocol. The correct jumper setting is shown below. Please notethat on earlier models the wire colours may change. These are relevant to the ‘TX’ - black wire asa blue wire and the ‘GND’ - white wire as a green wire.

1 2 3 4 5

6 7 98

External view of 9-way serial socket on the HFRRcontrol unit

Pin1

RS232 setting – P6

Serial connection – P4



9

1.4.2 PC Configuration - PCB Issue 3

The 3-way signal cable inside the control unit is connected to a 3-way orange header labelled‘RS232’. No jumper settings are required for this Issue of PCB.

RS232 SerialConnection



10

1.5 Temperature and humidity sensor

The sensor is only used with Issue 2 and 3 boards. The Issue 1 PCB does not have this feature.

Colour from connector To Board (pin) Signal

Brown P31 (1) Temperature

Green P31 (2) Supply (+5V)

Black P31 (3) Ground (0V)

Yellow P31 (4) Digital O/P

White P31 (5) Humidity

The temperature signal (P31/1, brown) is proportional to the measured temperature. 1°C = 0.01V,for example 23°C = 0.23V

The humidity signal (P31/5, white) is proportional to the measured humidity. 1% = 0.01V, for

example 55% = 0.55V



11

1.6 Power Supply

The power supply is an auto-sensing switch mode unit that can adjust input voltages from 100-240VAC.

Connections from the IEC mains socket to the power supply unit.

To IEC Colour From IEC Power Supply I/P

IEC Switch (L) Brown Link to IEC Power (L) 1

IEC Power (N) Blue Link to IEC Switch (N) 3

IEC Earth (E) Green/Yellow Link to Chassis 5

L L

IEC Switch

IEC Power

Power Supply Input

1LN

E

N L

N

E

2

3

4

5

Mains Power Input

Power Supply Input

Mains Switch



12

Connections from the power supply to PCB

From Power Supply To PCB (pin) Colour Function

1 (4 way header) P29 (+24V) Orange 24V

2 (4 way header) - - -

3 (4 way header) P29 (0V) Black 24V

4 (4 way header) GND Black Ground tag

1 (8 way header) P26 (+5V) Grey 5V

2 (8 way header) - - -


4 (8 way header) GND Black Ground Tag5 (8 way header) P28 (+12V) Red 12V

6 (8 way header) GND Black Ground Tag


8 (8 way header) P28 (-12V) White 12V

+

+

+

+

O

OO-

OO

+

O

24V P29

0V

+ 24V

0V

+ 12V

- 12V

0V

Power Supply Output

+ 5V

+ 5V

0V

0V

12V P28

5V P26

1

432

1234

67

5

8

PCB Input

24V - P29

12V - P28

5V - P26



13

1.7 Power Amplifier

The power amplifier provides power for the mechanical unit vibrator.

Later versions of the HFRR the amplifier are physically different (see below)but all connections and outputs are the same for both versions.

Old amplifier

FilterCapacitor

I/P +V

N

0V

-V

To Multiway(pin N)

To Multiway(pin P)

12V(red)

0V(black)

-12V(green)

AMP PWR OUT – P2

TO POWER AMP – P13

+ (orange)

- (black)

Power Amplifier

PCB



14

New Amplifier

This amplifier is the current version to be installed on the HFRR. Some olderversions of this model may have a capacitor attached to the PCB of the

amplifier. Newer versions do not require this.

Newer version with PCB (without capacitor)

From Power Amp Colour To PCB & multiway socket (pin)

Input Orange P13 (1)

+V Red P27 (+12V)

O/P Red/Blue Multiway socket (pin N)

0V Green/Red Multiway socket (pin P)

0V Black P27 (0V)

0V Black P13 (0)

-V Green P27 (-12V)

No Capacitor



15

1.7.1 Measuring the amplifier

To determine if the amplifier is faulty the input voltage from the PCB shouldbe checked first. Once a supply has been measured to the amplifier then

the output should be measured. To measure the input and output of thevibrator set the multimeter to Volts (AC).

The LVDT (stroke length) should also be checked as bad calibration or afault with the LVDT circuit will have an effect over the operation of the poweramplifier.

Input voltage to amplifier

The input voltage to the amplifier can be measured at P50 on the PCB withthe other probe connected to P20 (GND). This should read approximately

415 mV AC while running a test at 1mm stroke length.

Alternatively place the probes between the orange and black wires oforange connector P13 (to power amp) whilst still connected to the poweramplifier. The probes can be placed onto both screws of the orangeconnector to obtain a voltage reading. The reading should be approximately50 mV AC while running a test at 1 mm stroke length.

GND P20

Test PointP50

P13To poweramp



16

PCB connections Approximate input to amplifier @ 1mm stroke

P50415mV AC

P20 (GND)

P13 (Orange) Pin 150mV ACP13 (Black)

If no voltage is found from either test point then there is a problem with thePCB.

If the voltages are much higher than stated in the table above then therecould be a possible fault with the power amplifier draining too much powerfrom the circuit.

Amplifier output voltage

To measure the output of the vibrator place the probes between the twoconnectors located on top of the mechanical unit’s vibrator.

The output should measure approximately 1.5V AC @ 1mm stroke length.

Vibrator connector Approximate amplifier output @ 1mm stroke

Red wire1.5V AC

Blue wire

If the amplifier is found to be faulty, the case fan should also be checked. Insome circumstances the fan failing is the reason why the amplifier has faileddue to the fan not cooling the amplifier sufficiently [see case fan section].

Connect the multimeterprobes to the twoconnectors



17

1.7.2 Replacing the amplifier

1. Remove the 7 screws of the HFRR control unit cover.

2. Disconnect the cables that are linked with the amplifier. Thisrequires removing the orange connectors P27 and P31 [below].

To disconnect the wires linked to pins N (Red/Blue) and P (Green/Red)from the multiway socket, a pin extraction tool is required. This is usuallysupplied with the replacement power amplifier.

Insert the pin extraction tool into the multiway socket and push to extracteach pin highlighted below.

Remove orange connector – P27

AB

L

C

D

E

F

G

HJ

K

RM

N

P

Z

S

T

U

V

W

X

Y

External view of multiway socket on the HFRR control unit

N = Red/Blue P = Green/Red

Remove orange connector – P31

Multiway socket



18

3. Remove the 4 screws that hold the amplifier bracket locatedunderneath the control unit (see below).

4. Remove the defective power amplifier from the unit.

5. Follow the instructions in reverse to assemble.

Remove amplifier

bracket screws

Push extractor toolto extract wire



19

1.8 Fan Assembly

The HFRR control unit is cooled by one fan that is located at the rear of thecontrol unit. The fan is supplied by a 5V DC supply from P25 on the PCBand is constantly running when the unit is switched on. If the fan fails tooperate when the unit is switched on then this could result in the poweramplifier over-heating.

As the power amplifier is reliant on air flow into the HFRR control unit tooperate efficiently we recommend replacing the fan if it is found to beshowing signs of wear as to eliminate the possibility of any future loss of airflow into the unit.

The fan filter should also be checked by removing the fan guard outside thecontrol unit. If the filter is dirty then this should be replaced to combat loss ofair flow. The fan guard can be removed by hand without any tools involved.

Fan

Fan connector – P25



20

1.8.1 Testing the fan

Disconnect the orange connector of P25. Check if 5V DC is being suppliedfrom the PCB by measuring the voltage between pins 1 (Red- 5V) and 2

(Black - 0V) on the orange socket P25. If 5V is found then measure theresistance of the orange plug from the fan. The resistance should beapproximately 300-350KOhms

1.8.2 Replacing the fan

1. Disconnect the orange connector (P25) labelled ‘FAN’ on the PCB ifnot done so.

2. Remove the fan guard cover from the rear of the HFRR control unit.

Fan Guard Coverand Filter

4 screwssecuring thefan



21

3. The fan is held by four screws as shown below. Remove thesescrews by loosening the 4 nuts of each screw. The existing fixingscan be used to attach the new fan.

Remove the 4screws securingthe fan



22

1.9 Changing the Flash memory chip

For instruments with firmware upto 1.0.5, upgrading the firmware on theHFRR instrument involves physically changing the flash memory chip whichholds the firmware. The firmware version can be viewed by selecting theINFO button on the control unit menu.

Above 1.0.5, the firmware can be upgraded from a PC attached to theRS232 port. See ‘Updating HFRR firmware from v2.00 or higher’ manual. It is strongly recommended that the person carrying out the upgrade reads ALL of this document before starting work. All references to left and right

are when viewing the flash memory chip from the right side of theinstrument, i.e. when the writing on the flash chip is the correct way up.

Remove the 7 screws holding the cover in place (4 at the sides and 3 at theback). Carefully lift the cover (it is attached to the lower part of the case andPCB by several connecting cables) and lay to one side on the bench.Locate the flash memory chip, the larger of the two square devices at thefront right of the main PCB.

Before touching the PCB or the chips, touch a bare metal part of the case todissipate any static charge. Locate the chip extractor supplied with the newfirmware chip.

Flash memorychip

CPU



23

The extractor has two metal legs that protrude from the lower end. The chipsocket has two slots in opposite corners (top right and bottom left whenviewing the chip with the writing on it the right way up). Holding the extractorbetween thumb and forefinger, insert the two metal legs into the two slots at

opposite corners of the socket. Make sure that the legs go fully down intothe holes so that the plastic body of the extractor is flush with the surface ofthe chip.



24

Push down on the extractor and squeeze the two handles of the extractortogether using the thumb and forefinger. Do NOT attempt to pull the chipout of the socket – the action of squeezing the extractor will remove thechip. You have to squeeze the extractor quite hard, and it is important tosqueeze it at the ridged corners of the handles (this makes it easier). The

important thingNOT to do is to try and pull the chip out. This will break thechip and possibly the socket.

Place the extracted chip to one side. Be careful not to mix up the old andnew chips!

Lay the new chip in the socket in the same orientation as the removed chip.The top left corner of the chip is cut at a diagonal. This matches up with onecorner of the socket that is similarly shaped (see photos if you are unsure).

Check that the legs on the chip are correctly aligned in the grooves in the

Squeezehere



25

socket, and then using your thumb press the chip straight down into thesocket until the top of the chip is flush with the top face of the socket. If thereseems to be excessive resistance, check that the chip legs are correctlyaligned in the socket and try again.

Replace the cover but do not fit the securing screws. Before replacing thesecuring screws turn on the power to the instrument and check the softwareversion by pressing the INFO key. The new software version should beshown.

Replace the cover securing screws and return the old flash memory chip toPCS.

IMPORTANTYou will need to recalibrate ALL the instrument functions before using theinstrument (main temperature probe, alarm temperature, stroke length, forcetransducer and contact resistance). The calibration values for theinstrument are stored in the flash memory chip and will have been lost whenthe chip was changed.



26

2.0 Mechanical Unit

Servicing the HFRR mechanical unit

Chapter

2



27

2.1 Multiway socket

Function Colour QM SocketHeater1 Braid A

Heater1A Braid B

Heater2 Braid C

Heater2A Braid D

Microswitch 0V Black E

Microswitch White or Red F

LVDT Primary + Yellow/Red G

LVDT Primary - Yellow/Black H

LVDT Secondary + Red J

LVDT Secondary - Black KForce Transducer + Coax core L

Force Transducer - Coax screen M

Vibrator + Red N

Vibrator - Blue P

ECR + (LVDT Housing) White or Red R

ECR - (Ground Tag) Black S

Note. The LVDT secondary links together with green and blue.

AB

L

C

D

E

F

G

HJ

K

R

M

N

P

Z

S

T

U

V

W

X

Y

External view of the multiway socket onthe HFRR mechanical unit



28

2.2 Main/Alarm RTD and RTD probe socket

9-way RTD socket (pin) Description

1 Main RTD Probe socket (pin 1)

2 Main RTD Probe socket (pin 2)

3 Alarm RTD

4 Alarm RTD5,6,7,8,9 Not used

Main & alarm RTD Socket

1

2 3

4 5

6 7

9 8

1

2

3

Main RTD Probe Socket

Alarm RTD

External view of the 9-way main & alarm RTD socket and 3-way Main RTD probesocket on the HFRR mechanical unit



29

2.2.1 Testing the Main RTD Probe

The Main RTD resistance can be tested by measuring the resistance

between pins 1 and 2 of the Main RTD probe plug.

Main RTD Probe (pin) Resistance Notes

1110 Ohms Resistance at approx. 25°C

2

3 N/A N/A

Testing the Alarm RTD

Testing the Alarm RTD

There are two types of fault that can occur with the main RTD.

Open Circuit

If the measurement across pins 1 and 2 reads no resistance, then the mainRTD has become open circuit and requires replacing.

Short Circuit

Check if the probe pins 1 and 2 are not creating a short circuit to the probetip or protective braiding. If resistance is detected then this may cause thesystem to fail when the probe is inserted into the lower specimen holderwhen attached to the heater block.

3-pin plug connections of Main RTD probe

Pin 1

Pin 2



30

2.2.2 Testing the Alarm RTD

The alarm RTD assembly consists of a PT100 ceramic element attached bytwo PTFE insulated wires, red and black (or white). The alarm RTD element

is situated within the heater block of the HFRR unit.

The HFRR alarm RTD has the same characteristics as the main RTD probeand has a resistance of approximately 110 Ohms at room temperature. Theresistance of the alarm RTD can be measured between pins 3 and 4 on theRTD 9 way d-type socket at the rear of the HFRR mechanical unit as shownbelow.

Main RTD Socket

1

2 3

4 5

6 7

9 8

1

2

3

RTD Probe Socket

Alarm RTD

9-way socket Approx. Resistance Notes1

N/A Main RTD Resistance2

3110 Ohms

Alarm RTD Resistance atapprox. 25°C4

There are two types of fault that can occur with the alarm RTD.

Open Circuit

If the measurement across pins 3 and 4 reads no resistance, then the alarmRTD has become open circuit and requires replacing.

Short Circuit

Check if pins 3 and 4 are not creating a short circuit to the heater block orprotective braiding. If resistance is detected then this may cause the systemto fail (depending on resistance value) displaying an ‘Alarm TemperatureExceeded’ fault message or similar.



31

2.2.3 Replacing the Alarm RTD

To replace this component requires removing parts of the mechanical unit

with care.

Tools required:

Soldering iron and solder

Crosshead screwdriver

4mm Allen key

5mm Allen key

Please follow the steps below to replace the alarm RTD.

Remove the HFRR mechanical unit cover. This is secured by fourcrosshead screws. The cover should easily lift off to reveal the internalwiring of the HFRR mechanical unit. Carefully unsolder the two alarm RTDwires connected to pins 3 and 4 located on the 9 way D-Type socket at therear of the mechanical unit.

There are two types of Alarm RTD for the HFR.

1. The latest is an RTD housed in metal tubing that uses a spring toprotect the connecting wires.

2. The earlier is a ceramic type that uses a curved metal tube to protectthe connecting wires (shown on next page).

Main RTDconnections

(Pins 1 and 2)

Alarm RTDconnections

(Pins 3 and 4)



32

Please follow the steps below for the required Alarm RTD type.

Latest Alarm RTD Type

Unscrew Force Transducer cable, as shown above. Remove the AlarmRTD from the heater block. The heater cartridge above the Alarm RTD mayrequire being moved for easier removal. Replace with new Alarm RTD.

Earlier Alarm RTD Type

Unscrew Force Transducer cable, as shown above. Unscrew the bolt that

secures the Force Transducer using a 4mm Allen key, as shown above.Unscrew the two bolts that secure the Force Transducer block using a 5mm Allen key. Note that when the bolts are removed, the Force Transducer willonly be held at one end by the heater block and so great care must betaken not to apply too much pressure to the device.

To gain access to the alarm RTD, the curved metal tube protecting thewires must be removed. This is achieved by sliding back the block that heldthe Force Transducer in place. The metal tube can then be removed. Pullthe damaged Alarm RTD out of the heater block and replace with the newelement.

(Required for Earlier Alarm RTD Type)

Slide back block and tube

Remove Alarm RTD fromHeater Block

Force Transducer cable (Required for earlier AlarmRTD Type)

Unscrew the bolt that securesthe force transducer using a4mm Allen key.

(Required for earlier AlarmRTD Type)

Unscrew the 2 bolts that securethe force transducer block usinga 5mm Allen key.



33

Notes on putting the parts back correctly.

It is normally best to leave the soldering to the end, making sure the parts of

the mechanical unit are secured first. When securing the parts to themechanical unit, leave the two bolts shown on the previous page loose andfully secure the bolt to the force transducer, then tighten the two bolts fully.Don’t forget to attach the cable to force transducer. Re-solder the two wiresto pins 3 and 4 to the D-type socket and test the resistance.



34

2.3 Vibrator

The HFRR is fitted with a electromagnetic vibrator that drives the upper

specimen holder back and forth via a pushrod.

2.3.1 Testing the Vibrator

To test the vibrator windings, measure the resistance between sockets Nand P on the multiway connector. Alternatively measure the resistancebetween the two connectors located on top of the vibrator.

Multiway socket(pin)

Colour Approx. Resistance(Ohms)

Approx. Voltage (AC)@ 1mm

N (+) Red2 Ohms +/- 0.6 1.5V AC

P (-) Blue

The resistance should be approximately 2 Ohms. Zero or (more likely)infinite resistance indicates that the vibrator is faulty. If a standard test is runat 1mm the voltage should measure approximately 1.5V AC. If no or a lowervoltage is recorded then there may be a fault with the power amplifier inside

the control unit.

AB

L

C

D

E

F

G

HJ

K

R

M

N

P

Z

S

T

U

V

W

X

Y

External view of socket HFRRmechanical unit

Vibrator connectors



35

2.4 LVDT

Attached to the front of the vibrator is the LVDT and flexure housing. The

LVDT (linear variable differential transformer) is an electrical displacement-measuring device which allows the electronics unit to monitor the motion ofthe pushrod and adjust the frequency and amplitude of the vibrator asnecessary.

The LVDT has no contacting parts and is therefore unlikely to causeproblems.

When the iron core slides through the transformer, a certain number of coilwindings are affected by the proximity of the sliding core and thus generatea unique voltage output.

LVDT Housing

Flexure Housing



36

2.4.1 Testing the LVDT

It is possible to test the connections to the LVDT by measuring the

resistance between pairs of sockets on the multiway connector at the rear ofthe MTU.

The resistance between sockets G and H (the LVDT primary winding)should be approximately 41 Ohms. Between sockets J and K (the LVDTsecondary winding) the resistance should be approximately 1.6 KOhms.

Function Colour QM socket (pin)

LVDT Primary + Yellow/Red G

LVDT Primary - Yellow/Black H

LVDT Secondary link Green Not connected to socket(connected to blue wire ofsecondary link)

LVDT Secondary link Blue Not connected to socket(connected to green wire ofsecondary link)

LVDT Secondary + Red J

LVDT Secondary - Black K

Resistance of these two sides are shown below:

Function Approx. Resistance (Ohms)

LVDT Primary 41

LVDT Secondary 1600

AB

L

C

D

E

F

G

HJ

K

R

M

N

P

Z

S

T

U

V

W

X

Y

External view of the multiway socket on the HFRR mechanical unit



37

2.4.2 Testing the LVDT offset – PCB test point

Measuring the LVDT offset on the PCB is achieved by attaching amultimeter between P51 (LVDT Test Point) and P20 (Analogue and DigitalGround).

This measures/adjusts the voltage offset of the LVDT giving it a better rangeof stroke length for the pushrod. If the offset is significantly out then theLVDT fixing/position inside the mechanical unit may have come loose orthere is a fault with the PCB.

The voltage should display 2.29 V DC when the pushrod is idle.

P512.29 V DC at idle

P20

Note. If the HFRR unit is an upgrade this may not then be the case assome new control units have been setup without the HFR2 mechanicalunits present, hence the LVDT offset was never set precisely.

2.4.3 Adjusting the LVDT offset

To adjust the LVDT offset keep the multimeter probes attached to P51 andP20 and adjust POT 4 to achieve the desired voltage.

LVDT test point (P51)

Analog and DigitalGround (P20)

POT 4 (LVDT offset adjustment)



38

2.5 Heater block & Heaters

An aluminium heater block, containing two 24V, 15W electric heaters. The

upper surface of the heater block and the underside of the lower specimenholder are ground flat and care should be taken not to damage thesesurfaces, as this would impair the heat transfer to the lower specimenholder.

Supply to heaters: 24VDC

2.5.1 Testing Heaters

To test the heaters, measure the resistance between sockets A and B

(heater 1) and between C and D (heater 2) on the multiway connector at therear of the MTU.

Multiway socket (pin) Resistance (Ohms) Notes

A35

Approximate resistanceof Heater 1B

C35

Approximate resistanceof Heater 2D

AB

L

C

D

E

F

G

HJ

K

R

M

N

P

Z

S

T

U

V

W

X

Y

External view of multiway socket onthe HFRR mechanical unit

Two Heaters (24V, 15W)



39

Both measurements should be approximately 35 Ohms with standard(15W) heaters. Zero or (more likely) infinite resistance indicates that the

relevant heater is faulty.

Short circuit failure

The heaters can also suffer from short circuit resulting from the two wiresconnected to the element touching/shorting to the metal element case orprotective braiding. To test this, check if there is any resistance from theelement case and braiding to the multiway pin A, B, C and D for eachheater. If resistance is detected then this may cause the system to fail whenthe control unit supplies power to the heaters when a test is started.

2.5.2 Replacing Heaters

*Before starting this procedure - please ensure all power to the HFRRsystem is OFF. Remove the cover of the HFRR mechanical unit anddisconnect the multiway cable from the rear of the mechanical unit.

Locate the two metal braided cables that run from the two cartridge heatersinside the aluminium heater block and trace them back to the multiwayconnector at the rear of the mechanical unit. You will find that there are four

pins - two per heater. Heater 1 is connected between A and B, heater 2 isconnected between C and D (shown below).

Pin Description

A Heater 1

B Heater 1A

C Heater 2

D Heater 2A

Use the pin-extractor tool, to remove the first two pins relating to one of the

cartridge heaters (shown below). Remove the related heater cartridge frominside the heater block.



40

Take the new supplied cartridge and apply a small amount of heat transfercompound (shown below). Shake bottle before use.

Insert this new cartridge into the heater block (shown below)

Push the connector pins firmly into the multiway connector (where theoriginal cartridge connector pins were) until they are locked in (shownbelow).



41

Repeat this procedure for the other heater cartridge. Before the cover isplaced back onto the mechanical unit, make sure that the heater cables aretidily secured along the base of the HFRR so that they do not interfere withthe vibrator. The mechanical unit cover is now ready to be replaced.

Replace all of the external connections. The HFRR is now ready for use.



42

2.5.3 Replacing the heater block

Tools Required: 2.5mm Hex Key, 4mm Hex Key, 5mm Hex Key and 7mmSpanner.

1. Remove the cover of the HFRR mechanical unit. This is secured by4 crosshead screws, 2 either side.

2. Remove the cap head screw that holds the force transducer usingthe 4mm hex key.

3. Remove the 2 cap head screws using the 5mm hex key.

Remove the 2 cap head screws using the 5mmhex key

Heater Block

Force Transducer

Remove the cap head screwusing the 4mm hex key

Flexiblesupports



43

4. Carefully remove the two heater cartridges, Alarm RTD and theforce transducer cable from the heater block.

5. Slacken the nut that holds the force transducer to the heater blockusing the 7mm spanner. Do not unscrew the nut completely, as thenut will act as a marker for how much the force transducer should bescrewed into the new heater block later.

6. Remove the 4 cap head screws with the 4mm hex key that securesthe flexible supports and heater block to the base. The ECR groundtag is secured by one of the cap head screws [shown on next page].

Slacken the nut holding

the Force Transducerusing the 7mm spanner

Pull back to remove Alarm RTD from theheater block

Remove theHeater cartridgesfrom the heaterblock

Remove the ForceTransducer cable



44

7. Unscrew the Force Transducer from the heater block by hand.

8. Remove the 4 cap head screws holding the flexible supports to theheater block using the 2.5mm hex key.

Follow the steps in reverse order to complete installation of the new heater

block.

Remove the 4 cap headscrews

ECR Ground Tag

Unscrew the ForceTransducer from theheater block

Remove the 4 cap head screwsusing the 2.5mm hex key

Flexible supports



45

2.6 Force Transducer

The heater block is longitudinally restrained by a piezoelectric force

transducer that measures the friction force generated between the twospecimens as they slide relative to each other. This force transducer isrelatively much stiffer than the flexible supports and this ensures that themajority of the friction force appears at the transducer rather than at thesupports.

The force transducer is attached to the rear of the heater block by a short(30mm long) stainless steel link rod (as shown below).

2.6.1 Testing the force transducer

Checking the voltage

Unscrew the cable connector at the side of the force transducer. Measurethe voltage between the centre pin (positive) and the outer contact ring(negative). It should be approximately 25-30V (DC).

Force Transducer connector polarity

Force Transducer Approx. Voltage (DC) Notes

Centre pin (+)25 - 30

Positive (+)

Outer contact ring (-) Negative (-)

Force transducer cableconnector

Outer contact ring, Volts (-)

Force Transducer linkrod

Force Transducer

Connector pin, Volts (+)



46

Checking the cable

Check the continuity and internal resistance of the force transducer cable ifthere is no voltage measured from the cable.

With the connector removed from the force transducer first check thepositive connection of the cable. Place one probe on the positive (+) pin ofthe connector and the other probe on pin ‘L’ of the multiway socket at therear of the mechanical unit. To check the negative (-) connection of thecable place one probe on the outer contact ring of the connector and theother probe on pin ‘M’ of the multiway socket.

If the cable is found to be faulty then the wires of the cable could be makingbad connection with the crimp connectors that insert into the multiwaysocket. These can sometimes be re-soldered to correct the fault.

AB

L

C

D

E

F

G

HJ

K

R

M

N

P

Z

S

T

UV

W

X

Y

External view of the multiway socket onthe HFRR mechanical unit

Force Transducerconnector

Outer contactring, Volts (-)

Connector pin,Volts (+)



47

Checking the PCB

If no voltage is found from the mechanical unit then disconnect the multiway

socket from the control unit and open the control unit cover. Disconnect theforce transducer orange connector inside the control unit (this is theturquoise and grey wires) see below. Place the probes over the open pins ofthe orange socket (P18) and measure the voltage (‘+’ volts is turquoise(pin1) and ‘–‘ is grey). The voltage should measure approximately 30 VoltsDC.

PCB (P18) Voltage polarityTurquoise (pin1) +

Grey -

Measuring the voltage on the PCB is also achieved by attaching anoscilloscope or multimeter between P52 (Force Transducer Test Point) andP20 (Analogue and Digital Ground) as shown below.

Remove - ForceTransducer orangeconnector - P18

Pin 1 (+) as marked on PCB

Force Transducer

test point (P52)




48

The table below shows the force transducer voltage without any pressureapplied.

Test Point Approx. Voltage (DC)P52

2.5P20 GND

The change in voltage can be achieved by applying pressure to the front ofthe heater block. The output will increase as pressure is applied. Maximumvoltage 5V (dc)

Apply pressure here



49

2.7 The Fretting Flexure Lock

The fretting fixture lock is used for very small stroke length tests (<0.1mm)

When the knurled sleeve of the HFRR is screwed inwards (clockwise,towards the vibrator) the flexures are locked for fretting. When screwedoutwards to its full extent (anticlockwise, away from the vibrator), the systemis set for normal use (i.e. large stroke lengths).

Fretting Position

On Clockwise (screwed inwards)

Off Anticlockwise (screwed outwards)

The fretting lock is turned approximately three and a half turns from fully onto fully off. When the fretting lock is disengaged (normal position), somethreads will be visible as shown above. When the lock is engaged, thethreads will not be visible.

To test the fretting flexure lock microswitch follow the procedure belowThe fretting flexure lock has a microswitch attached so that the software candetect when the flexure lock is engaged.

THREADS VISIBLE

FRETTING LOCK

FRETTING LOCK OFF(STANDARD)



50

2.7.1 Testing the microswitch

Measure the resistance between sockets E and F on the multiwayconnector at the rear of the MTU. With the flexure lock engaged (screwedin) the resistance should be zero (switch closed). With the flexure lockdisengaged (screwed out) the resistance should be infinite (switch open).

AB

L

C

D

E

F

GH

J

K

R

M

N

P

Z

S

T

U

V

W

X

Y


MICROSWITCH



51

2.8 ECR (Electronic Contact Resistance)

The contact resistance circuit applies a 15 mV potential across thespecimen contact and a balance resistor in series. The contact and thebalance resistor thus form a potential divider circuit. The series resistance isset by the electronics unit and is set to 10 Ohms by default. This givessatisfactory results when testing diesel fuels. The potential drop across thecontact is thus a measure of the contact resistance, as compared to thebalance resistor.

2.8.1 Measuring the ECR voltage from the mechanical unit

The instrument needs to be switched on for this test.. With the upper

specimen holder out of contact with the lower specimen holder, measurethe voltage between the pushrod and heater block. It should beapproximately 15 mV (dc).

If no voltage is found then there could be a break in the wires, either themechanical unit, connecting cable or control unit.

If no break is found then measure the voltage from the PCB as described

later in this section.

Pushrod

Heater Block



52

2.8.2 Testing the ECR connections

To test the connections to the ECR (film) circuit, measure the resistancebetween sockets ‘R’ to the pushrod and ‘S’ to the heater block on the

multiway connector at the rear of the MTU. The internal resistance shouldbe lower than 1 Ohm.

2.8.3 Measuring the ECR voltage from the PCB

If no voltage is found then disconnect the multiway socket from the control

unit and open the control unit cover. Disconnect the ECR orange connectorinside the control unit (this is the yellow/red and white/red wires) see below.Place the probes over the open pins of the orange socket (P16) andmeasure the voltage (‘+’ volts is yellow/red (pin1) and ‘– ‘ is white/red). Thevoltage should measure approximately 15mV DC.

AB

L

C

D

E

F

G

HJ

K

R

M

N

P

Z

S

T

U

V

W

X

Y


Pin 1 (+) as marked on PCB

Remove - ECR orange connector - P16



53

PCB (P16)) Voltage polarity

Yellow/red (pin1) +

White/red -

Measuring the voltage on the PCB is also achieved by measuring thevoltage between P53 (ECR Test Point) and P20 (Analogue and DigitalGround).

The voltage should be around 4V at open circuit and 0V when closed circuit.

Open Circuit (pushrod not in contact with the heater block)

PCB Voltage when connected toHFRR control unit. Approx.

Description

P534V (dc)

ECR Test Point

P20 Analogue & Digital GND

Closed Circuit (pushrod in contact with the heater block)

PCB Voltage when connected toHFRR control unit

Description

P530V (DC)

ECR Test Point

P20 Analogue & Digital GND

ECR test point (P53)




54

2.9 Measuring the frequency

This guide describes the use of the HFRR frequency meter. This is used tocheck the oscillation frequency of the HFRR system.

Connect the BNC end of the cable supplied to input ‘A’ of the meter. Remove the mechanical unit cover and connect the banana plugs to thebanana sockets on top of the vibrator as shown below (red to red, black toblack).

A measurement time of 1 second is recommended. Press the time buttonuntil ‘1s’ is indicated on the display.

Press the ‘Freq A’ button to select input ‘A’ to measure frequency. Switch the meter on and then press the ‘Time’ and ‘Hold’ keys together.This activates the 50 kHz low pass filter which must be used when thefrequency is measured. Ensure that the ‘Freq’ wording is flashing. Thisindicates that the low pass filter is active.

Position the frequency meter on the bench such that the leads are not underany strain. Start a test in the normal way (a load is not required) andobserve the measured frequency.

Left: Frequency lead connections to mechanical unit vibrator

Right: Frequency meter supplied by PCS



55

2.10 Replacing the Push Rod Insert

Tools required:

Phillips screwdriver

2.5mm Allen key

7mm Spanner

Remove the main cover from the mechanical unit.

The small microswitch mounted on the vibrating arm will need to beremoved. This is secured using two small screws as shown below.(Depending on the age of the instrument, the switch may be mounted in a

different orientation).

Before the switch is removed, make a note of its orientation (there is a smallred button protruding from one end as shown on the next page).

Ensure that the switch is replaced in the same orientation.

Remove the two screwssecuring the microswitch



56

Remove the 4 socket screws indicated below. Be careful when removingthe housing to the vibrator assembly, as there is a microswitch pin that mayfall-out.

Pull forward the front part ONLY of the vibrator assembly. Do not removeany other parts. The front part is located on two dowels as shown below. Again make a note of the orientation since it will need to be replaced in thesame way.

SMALL BUTTON

Caution!Microswitch pin



57

Hold the locknut indicated, with a 7mm spanner and remove the push rodinsert. If necessary, use the upper specimen holder to grip the push rodinsert.

Fit the replacement push rod insert, such that the ball is located directly overthe centre of the lower specimen holder. One way to align the push rod is tofit the calibration device to the rig as you would if calibrating the force. If thepush rod is in the correct position then the edge of calibration device shouldfit flush with the heater block.

LOCKNUT

Dowel location



58

Fit the upper specimen holder and ensure that it is level before tighteningthe locknut.

Reassemble the rig in the reverse order to that detailed above.Please contact PCS instruments if you have any queries or questionsregarding this procedure.

Edge of calibration device inline with heater block



59

3.0 Accessories

HFRR Accessory maintenance

3.1 HFRR Microscope and Micrometer

3.1.1 Fitting the Micrometer to an HFRR Microscope Ball Stage

These instructions describe how to removable and assemble a newmicrometer for the HFRR microscope.

Tool required: PCS Spanner

Parts required for installation [shown above]

Assembly instructions

The micrometer can be removed from the ball stage whilst attached to themicroscope by unscrewing the nut with the spanner supplied by PCS. Thereare two notches located on the nut where the spanner can locate. Note thatwhen securing the micrometer with the ball stage, take care not to overtighten as this could result in the spanner slipping or damaging the notcheson the nut.

Chapter

3

PCS Spanner

Micrometer Spacer

Nut

Ball Stage includinglocation plate



60

Note in the picture below, how the spacer and nut are located when themicrometer is attached.

Nut

Micrometer Spacer



61

3.2 Humidity Cabinet

In very rare cases the humidity cabinet may develop a fault. There are afew components that can be tested to determine the fault. All of thecomponents except the fuse require the control panel case to beopened. It is advised that caution is taken when removing the panelenclosure as terminals are open to mains voltage.

3.2.1 Testing the Heaters

Testing the Fuse

Before testing the heaters it is recommended that the fuse is checked.

The fuse can be found at the back of the control panel.

Testing the resistance of the heaters

By testing the resistance of the heaters this will determine that theheaters are not damaged. To test the resistance of heaters the controlpanel cover will need to be removed to access the heater terminals.There are two hex screws either side of the panel and two on top.

When the cover is removed place the multimeter probes over the twoheater terminals to measure the resistance.

230VAC = 340 Ohms Approximately

110VAC = 59 Ohms Approximately

Zero or (more likely) infinite resistance indicates that the relevant heater isfaulty.

Heater terminal



62

Testing voltage to the heaters

The voltage is measured in the same way as the resistance was checked.Place the probes over the heater terminals to measure the voltage. The

voltage should be either 230 or 110V AC depending on input.

3.2.2 Testing the Temperature Sensor

In some cases the temperature sensor may become faulty and inhibit theheaters from being switched on. The sensor is connected to the white 5 wayconnector on the PCB with green and orange or red wires. The resistanceshould be approximately 10K Ohms between pins.

To disable this component and enable the heaters to be permanentlyswitched on (for means of testing for a short period only) the pins need to beremoved from the white connector. To remove the pins, a small flat headscrewdriver is needed to push down the clip holding the pin place and thenthe wire and connector can be pulled out.

Wire colours can vary but the pin location is always the two wires at the endof the connector as shown below.

If all tests fail to find the fault then the PCB may need replacing.

Two wires fortemperature sensor

Push down clip withscrewdriver to

release pin



63

3.2.3 Testing the temperature control dial

The temperature control dial is located at the front of the control panel as

shown below.

This is connected by the red, orange and black wires to the white connectoron the PCB.

The temperature control dial can be tested by a resistance check by placingthe probes between the red, black and orange wires. If the dial is making a

change in resistance when moved then it is working ok. Please note thevalues below are only approximate.

Probes between Red and Black wires

10K Ohms

Probes between Red and Orange wires

0°C = 130 Ohms30°C = 5K Ohms

50°C = 10K Ohms

Probes between Black and Orange wires

0°C = 10K Ohms30°C = 5K Ohms50°C = 130 Ohms

Temperaturecontrol dial

Connectedhere

Rear view of dial wire output



64

3.2.4 Replacing the Fan

The fan inside the humidity cabinet circulates the temperature and humidity.

If the fan stops working this can therefore affect the temperature andhumidity circulation causing unstable test conditions.

The fan is directly linked to the on/off switch on the control panel. It istherefore either 230VAC or 110VAC depending on supply to the cabinet.

The fan is held by four screws as shown below. Remove the screws toreplace the fan.

Depending on age of machine the fan will either be hard-wired straight tothe on/off switch (older units) or have connectors on the fan so it can beeasily replaced (later units).

Replacing the fan on older units

If the unit is hard-wired then the panel at the back of the unit will need to beremoved if the wire is not long enough to be pulled through to re-solder tothe new fan.

The back panel is held by two screws. The panel will not completely removeas the ground wire is attached as shown on the next page.

Unscrew to remove fan



65

The fan is usually connected by two black wires through a grommet in thecabinet as shown above. It is recommended to cut the wires higher up onthe panel so the fan can be pulled inside the cabinet, just enough for thewires to be cut on the old fan and be re-soldered onto the new fan. By dothis the wires do not need to be re-inserted through the grommet.

Once the fan is replaced then the wires can be pulled back to their original

position and re-soldered to the cut wire.

Alternatively the complete fan wire assembly can be replaced from on/offswitch to the fan. This would require removing the top control panel to gainaccess to the switch. The panel is held by six screws as described earlier inthe section 3.2.1.

Unscrew to removeback panel

Wires to fanthroughgrommet

Cut fan wiresat this level asdescribed ininstructions



66

4.0 Troubleshooting

4.1 HFRR Control Unit error messages

Error Message Troubleshooting

Temperature failed to

stabilise

Check that the Main RTD is correctly positioned

inside the lower specimen holder.Check that the instrument isn’t near a strong flowof air (such as very fast air extraction).

Check that there is good contact between theunderside of the lower specimen holder and thetopside of the heater block. In particular, checkthat the edges of the upper specimen holderaren’t damaged. Even a small air gap betweenthe lower specimen holder and the heater blockwill give temperature stabilisation problems.

Check if the heaters are not creating a shortcircuit.

Alarm temperatureexceeded

If a test has been started. Check that the MainRTD is correctly positioned inside the lowerspecimen holder.

Check that the main RTD is functioning correctly

Check that the alarm RTD is functioning correctly.

Check the connections between the main andalarm RTD from the mechanical unit.

*Check Main

Temperature Probe* - A to D converterreading 0 – ProbeShort circuit orunplugged?

Check that the main RTD is functioning correctly.

Check if the orange main RTD plug (P14)connected to PCB is unplugged or loose. If theorange plug is not unplugged, then swap theMain RTD orange plug with the Alarm RTDorange plug. Switch off and on again. If the PCBcircuitry for the main RTD is working then themessage next time should display an Alarm RTDfault.

Chapter

4



67

*Check MainTemperature Probe* -

A to D converteroffscale – Probe Shortcircuit or unplugged?

Check if the main RTD probe is connected.

Check that the main RTD is functioning correctly

Check if the RTD connecting cable is connected.

*Check AlarmTemperature Probe* - A to D converterreading 0 – ProbeShort circuit orunplugged?

Check that the alarm RTD is functioning correctly

Check if orange alarm RTD plug (P15) connectedto the PCB is unplugged or loose. If the orangeplug is not unplugged, then swap the Alarm RTDorange plug with the Main RTD orange plug.Switch off and on again. If the PCB circuitry forthe alarm RTD is working then the message next

time should display a Main RTD fault.*Check AlarmTemperature Probe* - A to D converteroffscale – Probe Shortcircuit or unplugged?

Check that the Alarm RTD is functioning correctly.

Check if the RTD connecting cable is connected.

RH/Temp probe notrespondingRH/Temp probe notresponding (cont...)

Check that the temperature probe is connected.The RH/Temp probe requires PCB Issue 2onwards to operate.

If running from a PC, start the instrument instandalone mode and check that the ambient

temperature and humidity are displayed on thescreen (firmware version 2.** and above only)

Connect the hygroclip directly to the connector atthe rear of the electronics unit. If this cures thefault then the problem is with the connectingcable.



68

4.2 General troubleshooting problems

4.2.1 Wear scar outside standard

Check that the reference fuel has not been contaminated (usuallycauses wear scar to be too low)

Check that the counterweight is in correct position (i.e. load armhorizontal with upper specimen fitted)

Check that the calibration constant are within correct limits

Check the ambient temperature and humidity are within specifiedlimits

Ensure that the correct test cleaning procedure is being followed

4.2.2 Incorrect stroke length

Ensure the LVDT is correctly calibrated and the stroke lengthcheck is within limits

Ensure the fretting fixture lock is disengaged (see section 2.7)

4.2.3 No Film/ECR and heaters unstable

Check heaters for signs of short circuit.

4.2.4 No connection to PC - PC software does not recognise instrument

The PC software must be started before the HFRR control unit is switchedon. The blue light on the HFRR control unit will light up if the PC softwarehas established connection to the control unit. If the blue light stays on for afew seconds after power-up and then goes out then follow the checklistbelow.

Check the serial cable between the PC and electronics unit. Notethat the serial cable supplied by PCS has straight throughconnections. The majority of commercial serial cables are ‘null-modem’ which have some connections crossed over. These will notfunction correctly if used with the HFRR system.

Check that the PC’s COM port is set to the correct setting. The HFR-PC software is pre-set to use COM1. If another peripheral is usingCOM1 then the software settings must be re-configured to anotherCOM port setting to operate the HFRR control unit. To change this

setting, go to options in the HFR-PC software and select ‘Comms



69

Settings…’. To check if the com port is configured properly on thecomputer go to control panel > Administrative tools > Computermanagement > Device manager (in system tools). Select ports(COM) from the list if available and check settings. If not present

there is a problem with the computer com port installation/setup.

Check the RS232 serial connection inside the HFRR control unit.[see PC connection in HFRR control unit section]

4.2.5 HFRPC software shuts down while a running a test

Check the heaters for signs of short circuit to the heater block.

If using a PC to control the HFRR. Check the power optionssettings on the PC. All settings should be disabled such as harddrive and hibernation mode.

To check if the power settings on the PC are correct, open Windowscontrol panel and select power options. The important settings aresystem standby set as ‘Never ’ and turn of hard disks also as‘Never ’. The ‘Hibernate’ function should also be disabled as shownbelow.



4.2.6 PC software displays “the instruments date and time is different from

the computer date and time” every time the software is loaded.

Restart the HFRR control unit in standalone mode. If the time and date

displayed on the LCD is set to zero, replace the battery inside the unit. Thebattery is located near the flash memory chip as shown below. If the HFRRcontrol unit battery is ok then the PC battery could be faulty. The batterytype is a CR2032 3V commonly found in PC motherboards.

4.2.7 Status bar displays “Main RTD Not connected”

Check main RTD calibration values. Possible corrupt calibration valuesdisplaying message, even though RTD probe is connected.

4.2.8 RTD Error message appears only when starting test

Check heaters for short circuit.

4.2.9 Cannot calibrate Force Transducer because pushrod keeps on running

Possible fault - Power amplifier or LVDT.

4.2.10 Control unit case becomes hot

Case fan is faulty resulting in power amplifier getting hot.

4.2.11 PC software error messages

Error message Troubleshooting for all messages

HFRR clock battery

hfrr service manual 02032011

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