Tty Submodule - Siemens S5-135U/155U System Manual

CPUs, Memory Cards, Memory Submodules, Interface Submodules
5.11.4

TTY Submodule

The TTY submodule is for use with the RK 512 computer link, data
transmission with procedures 3964/3964R, data transmission with the "open
driver."
The TTY submodule complies with DIN 66 258, Part 1.
Application
The TTY submodule can be inserted in the following CPU:
Interface Submodule ...
TTY submodule
Circuitry
The TTY submodule is equipped with a transmitter and receiver for 20 mA
current loop signals. Shown in the following figure is the typical circuitry for
current loop signals.
Figure 5-20
The loop current can be fed in both by the TTY submodule and by the
partner station. Only the side supplying the current is non-floating.
Caution
!
With longer line lengths, you should arrange your line so that the transmitter
always supplies the current.
5-106
For Use With ...
CPU 928B
CPU 948
–
Transmitter
+
+
–
–
Receiver
+
TTY Submodule: Loop Current Direction
+
Receiver
–
–
+
+
Transmitter
–
Current Direction Arrows
System Manual
C79000-G8576-C199-06