GE AF-650 GP Design And Installation Manual page 87

Application Setup Examples
Safe Stop Commissioning Test
After installation and before first operation, perform a
commissioning test of the installation making use of safe
stop. Also, perform the test after each modification of the
installation.
Example with STO
A safety relay evaluates the E-Stop button signals and
triggers an STO function on the adjustable frequency drive
in the event of an activation of the E-Stop button (See
Figure 6.31). This safety function corresponds to a category
0 stop (uncontrolled stop) in accordance with IEC 60204-1.
If the function is triggered during operation, the motor will
run down in an uncontrolled manner. The power to the
motor is safely removed, so that no further movement is
possible. It is not necessary to monitor plant at a standstill.
If an external force effect is to be anticipated, additional
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measures should be provided to safely prevent any
potential movement (e.g. mechanical brakes).
NOTE!
For all applications with Safe Stop it is important that short
circuit in the wiring to T37 can be excluded. This can be
done as described in EN ISO 13849-2 D4 by the use of
protected wiring, (shielded or segregated).
Example with SS1
SS1 correspond to a controlled stop, stop category 1
according to IEC 60204-1 (see Figure 6.32). When activating
the safety function a normal controlled stop will be
performed. This can be activated through terminal 27.
After the safe delay time has expired on the external safety
module, the STO will be triggered and terminal 37 will be
set low. Ramp-down will be performed as configured in
the drive. If drive is not stopped after the safe delay time,
the activation of STO will coast the adjustable frequency
drive.
NOTE!
When using the SS1 function, the brake ramp of the drive
is not monitored with respect to safety.
Example with Category 4/PL e application
Where the safety control system design requires two
channels for the STO function to achieve Category 4/PL e,
one channel can be implemented by Safe Stop T37 (STO)
and the other by a contactor, which may be connected in
either the drive input or output power circuits and
controlled by the Safety relay (see Figure 6.33). The
contactor must be monitored through an auxiliary guided
contact, and connected to the reset input of the Safety
Relay.
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TM
AF-650 GP Design and Installation Guide
Paralleling of Safe Stop input the one Safety Relay
Safe Stop inputs T37 (STO) may be connected directly
together if it is required to control multiple drives from the
same control line via one Safety Relay (see Figure 6.34).
Connecting inputs together increases the probability of a
fault in the unsafe direction, since a fault in one drive
might result in all drives becoming enabled. The
probability of a fault for T37 is so low, that the resulting
probability still meets the requirements for SIL2.
Figure 6.31 STO Example
Figure 6.32 SS1 Example
Figure 6.33 STO Category 4 Example
DET-767A