Terminating Resistors - JUMO variTRON 500 touch Installation Instructions Manual

3 Electrical connection
3.3.4

Terminating resistors

The terminating resistors of the RS485 interface are deactivated per default. To activate them, switches
1 and 2 must be closed.
The switches are located on the back of the device:
(1) Switches for terminating resistors (RS485)
Switch position: down = open, up = closed
NOTE!
To ensure fault-free operation, terminating resistors are required at the beginning and end of an RS485
transmission path.
28
+5 V
?
330
1
1
?
120
2
2
?
330
GND
(1)