Siemens SINUMERIK 840D sl Function Manual page 176

Connecting sensors and actuators
8.1 Safety-related input/output signals
Function
Safely reduced speed (SG)
Safe software limit switches (SE)
Safe software cams (SN)
Different signal run times in the channels
The signal timing in the two monitoring channels varies (the PLC cycle time takes up most of
the available time in the drive monitoring channel). To prevent the crosswise data comparison
function from being immediately activated after a signal change, a tolerance time is defined
using the following machine data.
For 840D sl:
MD36950 $MA_SAFE_MODE_SWITCH_TIME
For SINAMICS S120:
p9550 SI Motion SGE changeover tolerance time (Control Unit)
This data specifies the time period for which different signal states may be tolerated after the
SGEs have been changed-over before an error message is output.
Note
System-related minimum tolerance time:
2 x PLC cycle time (maximum cycle) + 1 x IPO cycle time
176
Minimum SGEs required
SBH/SG deselection
SBH deselection
SG selection, bit 1 (only for SG changeover)
SG selection, bit 0 (only for SG changeover)
Test stop selection (drive)
External stops
if gearbox stages are being used
Gear ratio selection, bit 2 (only if it is neces‐
sary to select the ratio)
Gear ratio selection, bit 1 (only if it is neces‐
sary to select the ratio)
Gear ratio selection, bit 0 (only if it is neces‐
sary to select the ratio)
SE selection (only for SE changeover)
Test stop selection (drive)
SBH/SG deselection (at least for test during
commissioning [start-up])
External stops
Test stop selection (drive)
SBH/SG deselection (at least for test during
commissioning [start-up])
External stops
Minimum SGAs required
SBH/SG active
Status, pulses cancelled (drive)
STOP A/B, C, D, E active (only if re‐
quired)
active SG stage, bits 0, 1 (only if re‐
quired)
SBH/SG active
Axis safely referenced
Status, pulses canceled (drive)
STOP A/B, C, D, E active (only if re‐
quired)
SBH/SG active
STOP A/B, C, D, E active (only if re‐
quired)
Axis safely referenced
SN1-, SN2-, ..., SN30 (only where re‐
quired)
SN1+, SN2+, ..., SN30+ (only if required)
Status, pulses cancelled (drive)
Function Manual, 12/2017, 6FC5397-4BP40-6BA1
Safety Integrated