Siemens S5-135U/155U - Manual (Page 235)

5-95
System Manual
C79000-G8576-C199-06
5.11.2 PG Submodule
By means of the PG submodule, you can use the second interface of the CPU
as the PG interface and equally privileged with the first interface.
The PG submodule can be inserted in the following CPUs:
Interface Submodule For Use With
PG submodule CPU 928B
CPU 948
The PG submodule is equipped with a transmitter and a receiver for 20 mA
current loop signals. The loop current is always fed in from the PG. The
following figure shows the circuitry for current loop signals of the standard
cable:
Transmitter
–
+
+
–
–
Receiver
Current Direction Arrows
CPU with
PG
+
Receiver
+
–
Transmitter
PG Module
–
+
–
+
Figure 5-11 PG Submodule: Loop Current Direction
The rate for data transmission via the PG interface is always 9600 bps.
Application
Circuitry
Data Transmission
Rate
CPUs, Memory Cards, Memory Submodules, Interface Submodules