low voltage lb status
DESCRIPTION
Low Voltage LB status. RPC detector and trigger group. Low Voltage Link Board status. After many failures in the link board system the RPC-Trigger community decided to investigate all the possible causes analyzing not only the LB system but also the LV system : A3016 boards MAO - PowerPoint PPT PresentationTRANSCRIPT
Low Voltage LB status
RPC detector and trigger group
Pigi Paolucci - CMS LV review 2
Equipment type Total installed spare % of spareSY1527 SY1527 5 4 1 25,0%
A3485 A3485 5 3 2 66,7%
A3512N HV 127 116 11 9,5%
A1676 BC A1676 20 17 3 17,6%
EASY3000S CRATE 40 38 2 5,3%
EASY3000 CRATE 44 39 5 12,8%
A3000FB FAN 27 23 4 17,4%
A3486S_380 MAO AC/DC 12 10 2 20,0%
A3009 LV DC/DC 105 96 9 9,4%
A3801A Temperature AC/DC 17 14 3 21,4%RPC HV distributor Barrel HV Distribution Box 37 35 2 5,7%A3486S_230 Endcap MAO AC/DC 13 12 1 8,3%RPC HV distributor Endcap HV Distribution Box 24 24 0 0,0%
A3016 LV DC/DC 68 64 4 6,3%
RPC LinkBoardBox LBB 105 96 9 9,4%
RPC MasterBoard MLB 351 300 49 16,3%
RPC SlaveBoard SLB 574 500 70 14,0%
RPC ControlBoard CB 124 120 4 3,3%
RPC LB FrontPanel LB FP 125 120 5 4,2%
RPC OptoBox OB 14 10 4 40,0%
7/6/10
Pigi Paolucci - CMS LV review 3
Low Voltage Link Board status
• After many failures in the link board system the RPC-Trigger community decided to investigate all the possible causes analyzing not only the LB system but also the LV system:
• A3016 boards• MAO• LV and MAO power cut and power cycle• Power off and on of the link box• CAEN firmware
7/6/10
A3016 behavior cutting the MAO 3Phase
Pigi Paolucci - CMS LV review 5
LV link board Schema
1. MAO 48 service from BC– Output current = 15-18 A
2. EASY 3000 – Joint 48 Power & Service
3. Output power from A3016:– 2.5 Volts / 5.0 Amp– 3.5 Volts / 10.0 Amp
MAO
SY1527
48 service
3-phase
EASYA3016
48 service48 power
Link Box7/6/10
Pigi Paolucci - CMS LV review 6
What powering OFF the MAO in the proper ways ?
• Powering OFF the MAO via SY1527 or using the interlock placed on the front
OK
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Pigi Paolucci - CMS LV review 7
What powering OFF the EASY in a “bad” way ?
• Powering OFF the EASY 3000 crate removing the power or service connector from the back
OK
7/6/10
Pigi Paolucci - CMS LV review 8
What cutting the MAO 3-phase ?
• Shutting-down the MAO cutting 3-phase
•oscillation does not depend from the MAO load (from 4 A to 18 A)
•sometimes 2 oscillations in few msec
•oscillation disappear separating the 48 power from the 48 service
•No other ways to reproduce it
NOT OK7/6/10
Pigi Paolucci - CMS LV review 9
What happen cutting MAO 3-phase ?• MAO goes OFF in 2 steps: from 48 to 22 V and a from 22 to 0 V • The A3016 channels go off when MAO voltage is around 22 V and
this takes about 250-300 msec (fixed load on the MAO)• Around 22 V the boards begin to work not properly (Vcc goes from
12 V to 6 V) and generates oscillations on Vout.
7/6/10
Vmao = 22 VVcc = 12 V
6 V
7/6/10 9Pigi Paolucci - INFN
Mao behavior during 3Phase glitch
Pigi Paolucci - CMS LV review 11
T0 T1
At T0:• Turn off the 3-phase switch• MAO starts ramping down with a “dummy load” - NO status changing • After a while, it gives UNV status, but the channel keeps status ON.
At T1:• MAO ramps down with different slope (real load)
At T2:• MAO swiched ON (600 ms from T0).
Switching OFF-ON in <1sec, no IntFail status is generated by the MAO and the channel goes back to the 48V without any alarm acknowledge.
T2
Scope output
MAO
A3016
40 V
7/6/10
Pigi Paolucci - CMS LV review 12
What we have done !Already implemented Solutions:
• Introducing a big capacitor (33 mF) between the service and power line of the EASY
• Improve the A3016 firmware • Modify the MAO firmware
Long Term Solutions:1. Designing a protection on the Link Box LV lines
(see tomorrow meeting) 2. Separating the 48 service and power of the
EASY ?7/6/10
OK
Under test now
Under test now
Pigi Paolucci - CMS LV review 13
A3016 firmware requirements• Couple of channels in tracking mode (ON/OFF/Trip at same time
and with one command).– delay between the 2 channels must be less than 1 msec
• Ramping up in stepping mode:– overshoot first steps < 10% of the setting voltage– overshoot of the last step must be < setting voltage– voltage must be always < setting voltage (no overshoot above max value)– Over-voltages are very dangerous for the LB.
– no under-voltage dips are allowed after VCC2.5 gets above 2.0 V– no under-voltage dips are allowed after VCC3.3 gets above 1.2 V– total time to reach the setting voltages (3.5 V and 2.5 V) should be less than 60
msec
7/6/10
Pigi Paolucci - CMS LV review 14
MAO firmware requirements
• The MAO behavior is case of glitch on the 3-phase line is potentially dangerous for the LV system.
• Turn OFF the MAO when the Vmon < 43-40 Volts in about 100 msec and require an acknowledge afterwards to bring the channel back to ON.– In 100 msec firmware measures the voltage 5 times,
should be enough.– After 100 msec the MAO voltage is around 35-38 V
and it is enough to shut-down properly the A3016.
7/6/10
Pigi Paolucci - CMS LV review 157/6/10
MAO
Vcc
Vout
New MAO firmware
old MAO firmware
Oscillations on both Vccand Vout
200 msecOFF – 38V
43V
New MOA firmware
Pigi Paolucci - CMS LV review 167/6/10
Rumping up - new A3016 firmware
50 msec
80 msec
2.5 V
3.5 V
No overshot over the max voltage
Pigi Paolucci - CMS LV review 177/6/10
Overshot - new A3016 firmware
Overshot < 10-15% voltage set
Pigi Paolucci - CMS LV review 187/6/10
Channels delay- new A3016 firmware
2 msec
Delay stable and < 2 msec (depends on the charge)
Pigi Paolucci - CMS LV review 19
Results with C and diode
power
service
1.5 sec
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Pigi Paolucci - CMS LV review 20
Results with C and diode
2.5 V
48 VNo spikes or oscillations
600 msec
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Pigi Paolucci - CMS LV review 21
Conclusions• Capacitor protection is working safe
• New firmwares are ready and under test at CAEN.• Next week will be tested at 904• Both Capacitor boxes and firmwares have been
payed by INFN (M&O-B 2010) 16 Keuro
• Hardware protection of the Link Box is in any case necessary
7/6/10