Travel To Fixed Stop With Programmable Clamping Torque; (Switchover Of Drive Actuator To Current-Controlled Operation); Simodrive 611A - Siemens SINUMERIK 840C Installation Instructions Manual

12 Functional Descriptions
12.24.4 Travel to fixed stop with fixed clamping torque (torque limitation via terminal 96)
Functional sequence
The control must switch the spindle to C-axis operation before the function is selected. It does
this by activating terminal E1 (C-axis operation) of the drive actuator.
The NC detects selection of function G221 (via G function or command channel) during block
processing and informs the PLC that the function has been selected via the interface signal
TRAVEL TO FIXED STOP ACTIVE.
The PLC then activates the free gear stage, in which the torque limitation is operative, via
terminals 117, 118 and 119 and outputs the interface signal ACKNOWLEDGEMENT TRAVEL
TO FIXED STOP ACTIVE to the NC.
The rotary axis then starts to traverse at the programmed velocity.
As soon as the C axis has reached the fixed stop, the following error increases. As a result of
the increase in the following error above the threshold set in NC MD 1280* or owing to the
input signal of a sensor (which is passed on to the PLC-NC interface), the control detects that
the fixed stop has been reached.
The NC setpoint interface then begins to output the current setpoint (NC MD 1144*).
The NC outputs the interface signal FIXED STOP REACHED to the PLC.
The PLC then activates terminal E5 of the actuator, thus effecting a switchover from speed-
controlled to torque-controlled operation. After a time period of > 80 ms, the PLC switches off
the torque limitation (by selecting the preceding gear stage).
In addition, the PLC also sends an edge signal ACKNOWLEDGEMENT FIXED STOP
REACHED to the NC.
The NC subsequently deletes the remaining distance to go and switches the axis to the "travel
to fixed stop active" status.
The axis setpoint output now outputs the current setpoint in accordance with the specified
torque (SD 320*).
A block change is then performed. The current setpoint, and thus also the clamping torque,
remain applied.
12.24.5

Travel to fixed stop with programmable clamping torque

(switchover of drive actuator to current-controlled operation)

This function can be implemented for
• axes in combination with the SIMODRIVE 611A drive actuator and for
• spindles with actuators of type SIMODRIVE 611A MSD or SIMODRIVE 660.
12.24.5.1

SIMODRIVE 611A

In this case, the drive actuator is switched to current-controlled operation by the PLC as soon
as the fixed stop is reached. When terminal 22 is activated, the voltage level applied to
terminals 20/24 is no longer applied as the speed setpoint, but as the current setpoint. In this
way, a variable clamping torque can be specified.
Setpoints must be input via terminals 24/20.
12–248
© Siemens AG 1992 All Rights Reserved
12.93
6FC5197- AA50
SINUMERIK 840C (IA)