User Manual

Bosch Rexroth AG
RE 95 320/06.06
DRC Travel Drive Control
5/20
Inch function
A second potentiometer can be connected for infi nitely variable
setpoint limitation.
For variants A and B, the inching potentiometer is monitored
for wire break and short circuit.
For variant C, the values at the input for the inching potentiom-
eter are specifi ed by an external control voltage. In this case
safety must be guaranteed by the connected signal source.
Travel behavior
Travel behavior is controlled by three variables.
• The setpoint is specifi ed via the joystick, the acceleration
pedal or the external control voltage (depending on the vari-
ant).
• The control of the PWM output for the specifi ed setpoint is
defi ned in the travel behavior characteristic.
• The acceleration behavior selected by the position of the
time ramp switch determines how quickly the control at the
PWM output changes.
Figure 2 shows the method of operation of the travel drive con-
trol. The following is a description of travel behavior for variant
A. The principles are the same for variants B and C:
• The joystick is in the neutral position when it is positioned
within a user-defi nable range around the zero position (dead
band).
If the joystick is in the neutral position, the PWM outputs for
the forwards and backwards directions that control the propor-
tional solenoids of the pump are switched off.
• If the joystick is moved to a position outside the dead band,
the current at the relevant PWM output (for forwards or
backwards travel) increases according to the position of the
joystick and the set characteristic. The corresponding pro-
portional solenoid is actuated. In addition, the acceleration
behavior can be selected via the time ramp switch. Three dif-
ferent travel modes can be parameterized ("soft", "medium",
"hard").
Start release
Start release is used to prevent the drive from starting uninten-
tionally.
For start release, a digital switched output is used. Its signal
must be integrated into the start control of the diesel engine.
The output is switched on if the joystick is in the neutral posi-
tion.
After the controller is switched on (ignition switch turned on),
the joystick must be in the neutral position in order for the start
release to be issued and the drive started
Speed monitoring
With speed monitoring, stalling of the diesel engine can be
prevented. This requires an additional speed sensor. With this
sensor, a speed threshold can be set. This threshold must be
exceeded before the drive can be started.
Special function
The special function can be used for different purposes and in
different modes:
• In "error lamp" mode, a signaling device such as an error
lamp can be connected in order to display various error
warnings through different fl ashing frequencies.
• In "backwards travel" mode, the special function is con-
nected as soon as backwards travel is selected. This can be
used for a warning signal or reversing light, for example.
• In "operating threshold" mode, a special function is connect-
ed when an operating threshold is reached. This could be a
vibration drive on a roller, for example. The threshold can be
set separately for forwards and backwards travel.
Figure 2: Method of operation of the DRC travel drive control, variants A-C (DRCA to DRCC)
Joystick
Inching
Evaluation
of inching
joystick
Characteristics
Time ramps
Ramp selection
(
"soft", "medium", "hard")
Evaluation
of direction
Evaluation
of special
switching
functions,
error lamp
Pump
control
(electr. current)
Special
switching
functions
0V/12V(24V)