llc load limiting control re 95 310/01.09 replaces: 03.06 ... · controlling a slew drive...

Linear Motion andAssembly Technologies ServicePneumaticsHydraulics

Electric Drives and Controls

LLC Load Limiting Control Application Software

Version 10 (LLCB) and Version 30 (LLCA) Electronic load limiting control for power management in hydraulic systems

RE 95 310/01.09replaces: 03.06

Features– The electronic load limiting control LLC is an easy-to-custom-

ize software system for managing power in hydraulic systems.

– The load limiting control LLC always matches the power input of an adjustable axial piston pump with the available power from the internal combustion engine.

– It prevents overloading of the internal combustion engine.

– The axial piston pump converts the maximum available power at all times.

– Two variants of the load limiting control LLC are available: Vari-ant A "Universal software" and variant B "Slew drive mode" for controlling a slew drive irrespective of the diesel engine speed.

– The load limiting control LLC is designed for axial piston pump from Rexroth.

– Adjustable parameters enable the user to easily customize the software for different configurations of pumps, internal com-bustion engines, sensors and machines.

– The load limiting control LLC is suitable for diesel engines with or without a CAN-bus interface, protocol SAE J1939.

– Diagnostics and parameterization are performed with the BODAS service PC software.

Inhalt

Type code 2

Variant LLCA 2Parameterization and diagnostics 6Required components 6LLCA connection diagram (without CAN bus) 7LLCA connection diagram (with CAN bus) 8

Variant LLCB 9Functional description 9Parameterization and diagnostics 10LLCB connection diagram 11Required components 12

Safety instructions 12

Data sheet

2/12 Bosch Rexroth AG LLC Load Limiting Control RE 95310/01.09

Variant LLCAWith the LLCA electronic load limiting control, it is possible to design the size of the diesel engine in the hydraulic system for the average power requirement and to reduce the power input of the individual consumers (pumps) in the event of an over-load. Thus, the load limiting control ensures optimum use of power from the diesel engine with varying loads.

The electronic load limiting control supports different hydraulic concepts and different diesel engine configurations. These concepts can be used in any combination.

The electronic load limiting control is designed for controlling variable displacement pumps in an open hydraulic circuit.

A distinction is made between the following hydraulic concepts for the purpose of control:

• With negative ID, the hydraulic system includes one or two A11VO variable displacement pumps or variable double pumps A8VO or A20VO, each with hydraulic power and load limiting controllers (LG1, LE, LA1).

Each pump is set to 100 % of the available diesel power.

The controller controls the pump controller (LE) and/or the pressure reduction valves (DRE) directly; the latter turn down the setting on the pump power controller (LG1, LA1) by means of an increased pilot pressure.

• With positive ID, the hydraulic system includes one or two A10VO variable displacement pumps with an FHD pump controller.

The total installed pump powers exceeds the diesel engine power.

The controller controls the pressure reduction valves (DRE) which in turn override the pilot pressures of the pumps, thereby reducing the flow rate.

A third, uncontrolled pump can be used with both hydraulic concepts. This pump has priority in the system. As a result, it receives the power it requires with no reduction. Whatever pow-er remains available is then divided between pumps 1 and 2.

Two different diesel engine configurations can be used:

• In the case of diesel engines without a CAN-bus inter-face, the controller receives the diesel engine's specified speed from an angle sensor (accelerator pedal position as specified speed) or from a fixed speed value set in the con-troller. The actual speed is measured using a speed sensor on the starter gear rim.

• In the case of diesel engines with a CAN-bus interface, the controller receives the necessary data for the load limit-ing control (specified and actual speed and/or torque and engine temperature) directly via the CAN bus.

It is also possible to use a combination of analog sensors and CAN-bus data.

Type code

AS/ LLC 1001 02 03 04

Type01 Application software AS/

Software02 Load Limiting Control LLC

Variante A

03 Load limiting control for two pumps Option: CAN bus, Option: Constant speed control A

Variante B

03 Load limiting control for one pump, Option: Slew drive Option: Power mode (switchable diesel power and speed drop) B

Version

04LLCB 10

LLCA 30

Ordering informationThe AS/LLC application software must only be used with the RC2-2/20 controller (variant B) or RC2-2/21 controller (variant A) and other add-on components (see page 11). When placing an order, the hardware and software type codes should be linked with a "+".

Example: RC2-2/21+AS/LLCA30

Bosch Rexroth AGRE 95310/01.09 LLC Load Limiting Control 3/12

Figure 2: Typical configuration for LLCA with CAN-bus interface

CAN-bus interface

Error lamp

RC2-2/21 controller with LLCA software

BODAS service PC software

Optional third pump on power take-off

Diesel engine with CAN interface

Pumps A8VO…LA1 or A11VO…LG1 / LE or A20VO…LG1 / LE or A10VO…FHD

Figure 1: Typical configuration for LLCA without CAN-bus interface

RC2-2/21 controller with LLCA software

Error lamp


Speed sensor

Diesel engine without CAN interface

Angle sensor

Pumps A8VO…LA1 or A11VO…LG1 / LE or A20VO…LG1 / LE or A10VO…FHD

Optional third pump

Variant LLCA


Functional descriptionFigure 3 illustrates how the load limiting control works:

• The load limiting control calculates the current speed drop of the diesel engine from the speed setting and the diesel characteristic depending on the set power mode.

The power modes are used to switch between three different permissible hydraulic powers. The switch is performed using switches which are connected to the controller.

In the case of diesel engines with a CAN interface, torque can alternatively be used for control purposes.

• The load limiting control compares the current speed drop with the parameterizable limit values. Different limit values can be parameterized for different specified speeds.

In case of diesel engines with a CAN interface, the temperature of the diesel engine can also be taken into account in this evaluation. As soon as the temperature value passes out of a parameterizable range, the limit value for the drop in engine speed is further reduced.

By externally specifying the reduction in power, the maximum power can be further limited. This is specified by means of a limit potentiometer connected to the controller.

• As long as the total of the hydraulic powers does not exceed the installed diesel power, the speed drop will not exceed the parameterized limit values. The load limiting control will not intervene.

• If, however, the diesel engine speed drop exceeds the limit value, the load limiting control will intervene and reduce the pump power.

The controller will calculate the available pump power as a control value.

• The pump power distributor shares the pump power deter-mined by the controller among the connected pumps.

The percentages used for sharing the available power between the connected pumps can be parameterized.

A switch on the controller also allows the operator to switch between two different distribution patterns.

Instead of pump 2, a valve can also be connected and parameterized for limp home mode or for precision mode.

Figure 3: How the LLCA load limiting control works

Safety switch

Specified speed

Actual speed

Temperature

Ext. power limiting

Power sharing 1

Power sharing 2

Limp home mode activated

Calculation Speed drop

Pump power sharing

Load limiting controller

Evaluation Speed drop

Pump 1

Pump 2

Power mode 2/3

Variant LLCA


Important features• The ratio in which the power reduction is distributed be-

tween pump 1 and pump 2 in the event of a limit load can be set as a parameter. Depending on the parameter setting, the power reduction may be distributed evenly between the two pumps, or the division may be asymmetrical.

A second distribution value of the power reduction can be set as an optional additional parameter. An external switch can then be used to switch between the two methods (power sharing mode switch).

• The total maximum permitted pump power can be reduced using an external potentiometer.

• An additional temperature mode is possible if a diesel engine with a CAN-bus interface is used. If the temperature passes above or below the limits set as parameters, power is re-duced to a user-definable level.

• Power modes: Switches between three different permissible hydraulic powers. These arise from the permissible speed drops that are specified differently for each power mode.

• Precision mode: A valve is controlled depending on the posi-tion of a dial potentiometer. The drop in LS pressure caused by the valve can be used to slow operating functions, e. g. for precision work.

• Automatic speed reduction: If no operating function is requested for a longer period of time, the diesel engine switches to idle mode to reduce fuel consumption. For this purpose, a pressure switch (normally closed contact) must be installed in an appropriate location. At low LS pressure, the pressure switch closes, signaling to the controller that automatic speed reduction is requested.

• If a diesel engine with a CAN-bus interface is used, the pres-ent output currents from pump 1 and pump 2 are sent via the CAN bus every 100 ms. This includes the power sharing set externally with a potentiometer and, if relevant, error mes-sages.

• The second proportional solenoid output can be used for limp home mode or for controlling a valve for the fine mode (parameterizable). Under normal circumstances this output produces a constant 100 %; this value falls to 0 % in the event of an error. Thus, the pumps can be switched by an external valve to an operating mode that enables the device to be run with no electronics.

• The inputs and outputs of the controller are monitored (for cable break, short-circuit). In the event of an error or if the safety switch is actuated, the drive is stopped immediately. All of the above errors as well as errors in the CAN commu-nication with the diesel engine and excessively high or low engine temperature can be indicated by a flashing code on a connected error lamp.

• All errors that occur are stored in the controller and can also be read later in plain text form using BODAS service.

Important parametersFor a diesel engine with a CAN-bus interface:

• Diesel engine data (specified speed and actual speed via CAN bus, specified torque and actual torque via CAN bus, dynamic behavior, permissible speed drop)

• CAN bus (baud rate, controller addresses, signal priorities)

• Configuration (number of pumps and limp home mode, power sharing, hydraulic concept, specified-speed source)

• Minimum and maximum magnetic current for pumps 1 and 2

• Load limiting control (dynamic controller data)

• Function (minimum/maximum temperatures, power reduc-tion)

For a diesel engine without a CAN-bus interface:

• Diesel engine data (actual speed from sensor, number of teeth on flywheel, dynamic behavior, permissible speed drop)

• Potentiometer for specified speed and power sharing

• Configuration (number of pumps and limp home mode, power sharing, hydraulic concept, specified speed source)

• Minimum and maximum magnetic current for pumps 1 and 2


Variant LLCA


Variant LLCA

Figure 4: Inputs and outputs on the controller (variant LLCA, configuration without CAN-bus interface)

LLCA connection diagram (without CAN bus)

10 A

30 +12 V/+24 V +

- 31

3 A

3)1 A

2 )

2 )

2 )

2 )

C D B E A H

1 )

8

20

9

21

13

41

42

27

1

2 28

32 33

43 44

17

7

18

22

46

47 38 35 36

34

45

52

24 50 51

29

3

15

31

30

RS-232 RxD

TxD

37

48

10

11

30 15

6)

49

Ignition lock7)

Voltage supply for the electronics

Power supply for the power outputs

Speed sensor (optional)

LS pressure (optional)

1)Short, low-resistance connection from a case screw to the device ground or vehicle ground 2)Separate ground connection from solenoid return line to battery (chassis possible) 3)Separate fuses recommended for switches, sensors and electronics 5)Sensor supply voltage for potentiometers and active sensors 6)Observe maximum current consumption where proportional solenoids and switched outputs are controlled simultaneously 7)Can be used as switch inputs if connected externally to GND

Sensor supply5) 2 x 5 V/30 mA

Freq

uenc

y in

puts

Pro

port

iona

l out

puts Main pump 1

Main pump 2, valve control for limp home mode or valve control for precision mode (optional)

Error lamp

Signal lamp for automatic speed reduction

Sw

itche

d ou

tput

sLo

w-s

ide

mea

sure

men

t in

put

Volta

ge

inpu

tsC

urre

nt

inpu

ts

5 V constant voltage

Tem

pera

ture

inpu

tsS

witc

h in

puts

Ground connection, case

Diagnostics connector for BODAS service

External specification of power reduction or specification for precision mode (optional)Angle position sensor on accelerator pedal or injection linkage (optional)

Teaching set speeds (optional)

Power sharing mode (optional)

Power mode 2 (optional)


Reserved


Variant LLCA

Figure 5: Inputs and outputs on the controller (variant LLCA, configuration with CAN-bus interface)

LLCA connection diagram (with CAN bus)

CAN H

CAN L

10 A

30 +12 V/+24 V +

- 31

3 A

3)1 A

2 )

2 )

2 )

2 )

C D B E A H

F G

1 )

4 )

8

20

9

21

13

41

42

27

1

2 28

32 33

43 44

17

7

18

22

46

47 38 35 36

34

45

40

39

25 26

52

24 50 51

29

3

15

31

30

RS-232 RxD

TxD

120 Ohm

37

48

10

11

30 15

6)

49

Ignition lock7)

Voltage supply for the electronics

Power supply for the power outputs

Speed sensor (optional)

LS pressure (optional)

1)Short, low-resistance connection from a case screw to the device ground or vehicle ground 2)Separate ground connection from solenoid return line to battery (chassis possible) 3)Separate fuses recommended for switches, sensors and electronics 4)CAN bus: 120 Ω termination resistor recommended 5)Sensor supply voltage for potentiometers and active sensors 6)Observe maximum current consumption where proportional solenoids and switched outputs are controlled simultaneously 7)Can be used as switch inputs if connected externally to GND

Sensor supply5) 2 x 5 V/30 mA

Freq

uenc

y in

puts

Pro

port

iona

l out

puts Main pump 1

Main pump 2, valve control for limp home mode or valve control for precision mode (optional)

Error lamp

Signal lamp for automatic speed reduction

Sw

itche

d ou

tput

sLo

w-s

ide

mea

sure

men

t in

put

Volta

ge

inpu

tsC

urre

nt

inpu

ts

5 V constant voltage

Tem

pera

ture

inpu

tsS

witc

h in

puts

Ground connection, case

Diagnostics connector for BODAS service

External specification of power reduction or specification for precision mode (optional)Angle position sensor on accelerator pedal or injection linkage (optional)

Teaching set speeds (optional)

Power sharing mode (optional)



Reserved


The LLCB electronic load limiting control functions in basically the same way as the LLCA variant, but is designed to control only one pump instead of two.

In addition, the valve for the slew drive is controlled in such a way that the flow rate for the slew drive motor is maintained irrespective of the diesel engine speed. As a result, the slew drive always turns at the same speed regardless of the speed at which the diesel engine is running.

The electronic load limiting control is designed for controlling variable displacement pumps in an open hydraulic circuit.

The following hydraulic concept can be used for control pur-poses:

• The hydraulic system consists of the axial piston pumps A8VO or A11VO with a hydraulic or electrohydraulic power controller and load limiting controller (LA1, LG1, LE) together with a control block (e.g. M7) with a pressure reduction valve (DRE) on the slew drive spool.

The RC2-2/20 controller controls the pump controller and the pressure reduction valve in the control block.

The following diesel engine configuration can be used:

• Diesel engine with or without CAN-bus interface The controller receives the specified speed for the diesel engine from an angle sensor (accelerator pedal position as specified speed). The actual speed is measured using a speed sensor on the starter gear rim. The LLCB variant does not evaluate the CAN bus.

Functional description

The diagram below illustrates how the load limiting control works:

• From the specified speed value and the diesel characteristic, the load limiting control calculates the current speed drop of the diesel engine.

• The load limiting control compares the current speed drop with the parameterizable limit values. Different limit values can be parameterized for different specified speeds.

• As long as the total of the hydraulic powers does not exceed the installed diesel power, the speed drop will not exceed the parameterized limit values. The load limiting control will not intervene.

• If, however, the diesel engine speed drop exceeds the limit value, the load limiting controller will intervene and reduce the pump power.

• The maximum permissible speed drop of the diesel engine can be adjusted in three steps using the "power mode" switches.

Figure 6: Configuration for LLCB

RC2-20 controller with LLCA software

Error lamp


Speed sensor

Diesel engine with or without CAN-bus

interface

Angle sensor

Pumps A8VO... LA1..F.4 or A11VO...LE / LG1

Slew drive GFB

Slew drive shaft in control block M7

Variant LLCB


Variant LLCB

Figure 7: How the LLCB load limiting control works

Specified speed

Safety switch

Teach

Actual speed

Power mode 2/3

Maximum power

Diesel characteristic

Calculation Speed drop

Characteristic Slew drive

Load limiting control

Slew drive shaft in control block

Working pump

Important features• The maximum flow rate of the slew drive motor can be

set using a characteristic irrespective of the diesel engine speed.

• Power modes: Switches between three different permissible hydraulic powers. These arise from the permissible speed drops that are specified differently for each power mode.

• Maximum power mode: A switched input, "Maximum Power", can be used to switch between reduced hydraulic handling power and maximum working power.

• The definition of the ratio of specified speed to actual speed can be executed in "Teach Mode" without BODAS service.

• All errors that occur are stored in the controller and can also be read later in plain text form using BODAS service.

Important parameters• Diesel engine data (number of teeth on the starter gear rim,

dynamic behavior, permissible speed drop)

• Potentiometer for specified speed

• Minimum and maximum magnetic current for working hydrau-lic pump and slew drive valve



Figure 8: Inputs and outputs on the controller (variant LLCB)

LLCB connection diagram

2)

2)

41

1

42

2

3332

37

48

28

A

B

31

30

29

1)

515017

52

TxDRS232 RxD

+L

CDBEAGFH

+5 V / 15 mA47

46

49

2)

1 A 3)

12V/24 V

0 V

8 A27

10

11

Ignition lock with starter non-repeat unit

Speed sensor

Angle position sensor on accelerator pedal or injection linkage

TeachMaximum power

Working pump

Control block - slew drive shaft

Error lamp

Diagnostics connector for BODAS serivce

1) Short, low-resistance connection from the plug connector and one housing screw to the device ground

2) Separate ground connection from the solenoid return line to the battery (chassis also possible)

3) Separate fuses for switches and sensors

Power supply

Supply of the power outputs

Erro

r det

ectio

n fo

r po

tent

iom

eter

s 1K

-5K

Power mode 2Power mode 3

Variant LLCB


Required componentsThe following electronic components are required:

• BODAS RC2-2/21 controller with 52-pin mating connector (RE 95201) and AS/LLCA software, Version 30

• BODAS RC2-2/20 controller with 52-pin mating connector (RE 95200) and AS/LLCB software, Version 10

• Speed sensor IDR (RE 95130) with mating connector for diesel engine without a CAN bus

• Angle sensor WS1 (RE 95140) with mating connector for diesel engine without a CAN bus

The following hydraulic components are required:

• Variable displacement pump with appropriate controller A8VO…LA1 (RE 93010) or A11VO…LG1 or LE (RE 92500) or A20VO…LG1 or LE (RE 93100) or A10VO…FHD (RE 92701)

• Possibly a mating connector, depending on the connector variant selected for the pump

• For A11VO…LG1, A20VO…LG1 and A10VO…FHD sepa-rate DRE4K pressure control valves (RE 29181) with mating connector and control oil pump

• Possibly an additional valve and mating connector for limp home mode (e.g. DRE4K...)

The following items are required for commissioning and service:

• BODAS service PC software (RE 95086)

• BODAS service connecting cable (RE 95086)

• Diagnostics socket (RE 95086)

Parameterization and diagnosticsThe parameters that need to be assigned for commissioning the LLC load limiting control can be set easily using the BODAS service PC software.

You can configure BODAS serivce to display the most impor-tant process data and the error messages for diagnostics and troubleshooting purposes.

12/12 Bosch Rexroth AG LLC Load Limiting Control RE 95 310/03.06

© This document, as well as the data, specifications and other information set forth in it, are the exclusive property of Bosch Rexroth AG. Without their consent it may not be reproduced or given to third parties.The data specified above only serve to describe the product. No statements concerning a certain condition or suitability for a certain application can be derived from our information. The given information does not release the user from the obligation of own judgement and verification. It must be remembered that our products are subject to a natural process of wear and aging.

Subject to change.

Bosch Rexroth AGHydraulicsMobile ElectronicsGlockeraustraße 489275 Elchingen, GermanyPhone +49 (0) 73 08 82-0Fax +49 (0) 73 08 72 [email protected]/mobile-electronics

Safety instructions• The suggested circuits do not imply any technical liability for

the system on the part of Rexroth.

• Lines to speed sensors must be shielded. The shielding is to be connected to the electronics on one side or to the machine or vehicle ground via a low-resistance connection.

• Lines to the electronics must not be routed close to other power conducting lines in the machine or vehicle.

• Sufficient distance from radio systems must be maintained.

• All connectors must be unplugged from the electronics dur-ing electrical welding operations.

• The electronics may only be tested with the proportional solenoids connected.

• The proportional solenoids must not be connected to spark suppression diodes.

• On/off solenoids at the outputs of the controller RC do not need to be connected to spark suppression diodes.

• Other inductive loads that are in the system but not con-nected to the controller RC must be connected to spark suppression diodes.

• In order to preserve the warranty, any installation or replace-ment of the RC software (flash EPROM) must be performed by Rexroth staff.

• Observe operating instructions RE 95310-01-B for the LLCA variant and RE 95311-B for the LLCB variant.

llc load limiting control re 95 310/01.09 replaces: 03.06 ... · controlling a slew drive...

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