Siemens SIMATIC S7-1500 System Manual page 73

Wiring
6.8 Front connector for the I/O modules
The three different front connectors are characterized as follows:
● 40 clamping points each
● Connection technology: Screw terminal (for 35 mm modules only) or push-in terminal
● Module width: 35 mm or 25 mm
● If you want to supply load groups with the same potential (non-isolated), use the potential
bridges supplied for the front connector. In four locations: 9 and 29, 10 and 30, 19 and
39, 20 and 40, the terminals can be bridged by means of potential bridges. Advantage:
Reduction of the wiring effort.
Note
Note that the potential bridges may only be deployed with a maximum rated voltage of
24 VDC! The current capacity per potential bridge is 8 A maximum.
Note that potential bridges are not available for front connectors for a module width of
25 mm.
● In the delivery state a coding element is located in the module. When the front connector
is first inserted into the I/O module, a part of the coding element clips onto the front
connector. When the front connector is removed from the I/O module, one half of the
coding element remains in the front connector, and the other part of the coding element
remains in the I/O module. The insertion of a front connector that is not suited to the
module is thereby mechanically prevented. Thus, for example, the front connector with
the coding element for a digital module cannot be inserted on an analog module.
Additional information on the coding element can be found in section Coding element at
the I/O module and at the front connector (Page 130).
Reference
Further information on the use of the potential bridges can be found in the manual for the
respective I/O module.
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S7-1500 Automation System
System Manual, 02/2014, A5E03461182-AB