Functional safety
326
9.
FUNCTIONAL SAFETY
Examples
316
DDS
HARDWARE
Ref.1310
9.3 Examples
Example 1. STO (Safe Torque Off) safety function with PL d or SIL 2
This STO safety function corresponds to an uncontrolled stop in accor-
dance with stop category 0 of IEC 60204-1.
Example 2. SS1 (Safe Stop 1) safety function with PL d or SIL 2
This SS1 safety function corresponds to a controlled stop in accordance
with stop category 1 of IEC 60204-1.
When requiring an SS1 safety function, it is necessary to use a safety re-
lay with delayed contacts and non-delayed contacts so as to do a con-
trolled stop before removing motor torque. See an example with this type
of operation.
Note. These examples use an external safety relay.
F. H9/2
STO safety function (with PL d or SIL 2) monitoring the status of both
channels with an external safety relay.
F. H9/3
SS1 safety function (with PL d or SIL 2).
KM1 auxiliary contact of - KM1 with EN 60947-5-1 approval
State definition: Drive Enable = 0
Torque Off
Positive logic
KM1 auxiliary contact of - KM1 with EN 60947-5-1 approval
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