JUMO 707020 dTRANS T02 LCD - Four-Wire Transmitter Operating Manual - Handbuch (Seite 72)

34
8 Connection examples
Example 1
Connecting a PLC to the open-collector output
Calculation example for R
A
(working resistance)
In this example, the following typical PLC characteristics are as-
sumed:
- for signal “1”:
13 — 30V
- for signal “0”: -3 to +5V
- input current for signal “1”: 7mA
An assumed input voltage of 18V/7mA for signal “1” results in the
following calculation:
Result: A resistance of 820
⍀ will be selected.
R
A
24V - 18V
7mA
-------------------------- 857.14
Ω
= =