Siemens SINUMERIK 840C - Manual (Page 960)

09.95 12 Functional Descriptions
12.19.3 Interlocks and monitoring
SW limit switch + 0
P
NC
P
SW P
M
P
1
Path distance to go IKA value
• IKA/TC motion in positive direction
• SW limit switch monitoring prior to traversal knows only P
NC
and does not therefore
output an alarm
• Alarm 148* is output during traversal when P
SW
is reached.
b) With an NC setpoint P
NC
, a machine position PM is reached during traversal as a function
of IKA/TC (negative IKA/TC motion).
SW limit switch + 0
P
M
P
SW P
NC
P
1
Compensation
value
Path distance to go
• IKA/TC motion in negative direction
• SW limit switch monitoring prior to traversal knows only P
NC
and therefore outputs
alarm 2065, "Programmed position beyond SW limit switch" even though machine
position P
M
belonging to this NC setpoint is located in front of the SW limit switch.
With IKA Stage 2, the time when the software limit switch is scanned depends on the axis
setpoint position. Monitoring in the position controller might result in a slight overshoot of the
software limit switch.
Effect of direction-dependent compensation - backlash compensation
When an IKA/TC table is defined with positive and negative output values, the output quantity
axis is moved in various directions. This does not however mean that this reversal of direction
is detected or evaluated by any other direction-dependent IKA compensation (backlash
compensation) which may be present. These types of compensation detect reversals of
direction on the basis of part setpoints at the output of the velocity control.
© Siemens AG 1992 All Rights Reserved 6FC5197- AA50 12–185
SINUMERIK 840C (IA)