$SSHQGL[
S7-300 Automation System, Hardware and Installation: CPU 31xC and CPU 31x
A5E00105492-03
12-27
+RZWR3URWHFW'LJLWDO2XWSXW0RGXOHVDJDLQVW,QGXFWLYH6XUJH
9ROWDJH
,QGXFWLYHVXUJHYROWDJH
Overvoltage occurs when inductive devices are switched off. Examples are relay
coils and contactors.
,QWHJUDWHGVXUJHDUUHVWHU
S7-300 digital output modules are equipped with an integrated surge arrester.
$GGLWLRQDORYHUYROWDJHSURWHFWLRQ
Inductive devices require additional surge arresters only in following cases:
• If SIMATIC output circuits can be switched off by additionally installed contacts
(e.g. relay contacts).
• If the inductive loads are not controlled by SIMATIC modules
Note: Request information on relevant surge protection rating from the supplier of
inductive devices.
([DPSOH
The figures illustrates an output circuit requiring additional overvoltage protectors.
Contact in the output circuit
Inductivity requires circuiting
CPU
PS
SM
SM
SM
SM
SM
SM
Figure 12-8 EMERGENCY-OFF relay contact in the output circuit
Refer also to the rest of the information in this section.
To Next Page
Loading...
Need help?
General
