Tty Submodule; Application; Circuitry - Siemens S5-155U System Manual

5.8.4

TTY Submodule

Application

Circuitry

System Manual
C79000-B8576-C199-03
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.
The TTY submodule can be inserted in the following CPU:
Interface Submodule... For Use With...

TTY submodule

CPU 928B
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.
-
Transmitter
+
+
-
-
Receiver
+
Figure 5-16 TTY Submodule: Loop Current Direction
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.
Interface Submodule
+
Receiver
-
-
+
+
Transmitter
-
Current Direction Arrows
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