Installing the S7-400
2-16
S7-400 and M7-400 Programmable Controllers Hardware and Installation
A5E00069481-04
2.6
Chassis Terminal Connection in the Non-Isolated
Configuration
Reference Point
The racks offer the option of connecting the 24-V load voltage ground in the
non-isolated configuration to the 5-V ground (reference potential M, logic ground).
Connect the chassis ground to the reference point for non-isolated modules. The
reference point is metallically connected to the reference potential M.
Note
The position of the reference point on the racks was changed in 10/99.
The following figure shows the position of the reference point on a rack up
until 10/99.
Chassis ground terminal
Reference point
1
2
3
4
5
6
7
Connecting to the Reference Point until 10/99
For the connection to the reference point, use a cable lug for M4, a suitable spring
washer (for example, strain washer to DIN 6796) and an M4 x 6 cylinder-head
screw.