Siemens SINUMERIK 840C - Manual (Page 1021)

12 Functional Descriptions 12.93
12.24.4 Travel to fixed stop with fixed clamping torque (torque limitation via terminal 96)
12.24.4.1 SIMODRIVE 611A
In this system, a fixed current limitation is specified via a resistor circuit (or via R12) in the
drive actuator. This current limit is then addressed by the control via a PLC output (which acts
on terminal 96 of the actuator) as soon as the function is activated. It can thus be ensured that
a fixed clamping torque is available at the axis.
Setpoints can be input via terminals 56/14 or 24/20.
Hardware connections:
24
56
96
14
Speed
controller Current
setpoint
limitation Current
controller
Simodrive 611A
Drive
Sensor
(option)
I
set
I
act
NC
PLC
Position
actual
value
Speed
setpoint
M T P
Actua-
tor
20
Functional sequence with analog drives
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 must then activate the current limitation in the actuator (terminal 96) and transmit an
edge signal ACKNOWLEDGEMENT TRAVEL TO FIXED STOP ACTIVE to the NC.
The axis then approaches the target position at the programmed velocity.
As soon as the axis reaches 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.
12–246 © Siemens AG 1992 All Rights Reserved 6FC5197- AA50
SINUMERIK 840C (IA)