Start Inhibithibit Inhibit The Drive Modules/Safe Standstill - Siemens 6SN1123-1AA00-0DA2 Configuration Manual

8 Important Circuit Information
8.5 Start inhibit in the drive modules/safe standstill
8.5 Start inhibit in the drive modules/safe standstill
8.5.1 Start inhibit applications
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The SIMODRIVE 611 drive control units support the "safe standstill" function –
this provides protection against unexpected starting according to the require-
ments of Appendix I No. 1.2.7 of the Machinery Directive 98/37/EC, DIN EN
954–1 Category 3 and DIN EN 1037. It is important that the information and the
instructions in this documentation are precisely adhered to.
For this purpose, the drive control units are provided by default with an internal
safety relay with forced contacts. In the Configuration Manuals and user manu-
als, this safety relay is called a "start inhibit" function or "start inhibit relay."
This safety relay galvanically separates the power supply of the optocouplers
for pulse transmission to the IGBT. The connected motor can no longer gener-
ate torque.
The "safe standstill" function prevents unexpected starting of the motor (from
standstill) that is connected to the drive control unit. The motor shaft is in a no–
torque condition when the "safe standstill" function is active. This is the reason
that this safety function should only be activated after the drive actually comes
to a standstill. Otherwise, it will not be able to brake. The external machine con-
trol must have first brought the machine to a standstill and ensured that this has
actually taken place (that the machine has come to a standstill).
Caution
The velocity should be zero prior to the "safe standstill" function.
Notice
When the start inhibit function is correctly used, the forced signaling contact
AS1/AS2 must always be included in the line contactor circuit or the
EMERGENCY STOP circuit. If the function of the start inhibit relay is not
plausible regarding the operating mode of the machine, then the drive involved
must be electrically isolated from the line supply, e.g. using the line contactor in
the infeed module. The start inhibit and the associated operating mode may
only be re–used again after the fault has been removed.
SIMODRIVE 611 Configuration Manual (PJU) – 02/2012 Edition
© Siemens AG 2012 All Rights Reserved
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