IM-P198-02
MI Issue 5
27
4.2.5 4-20 mA current loop multiple inputs and outputs
It is not altogether obvious how to wire multiple 4-20 mA current loops without inserting
too many wires into the 24 V and GND terminals. One technique is shown in the following
wiring diagram - Figure 24, which depicts the worst case, which is 3 inputs and 3 outputs
at the same time. In this example no more than 2 wires are tied to any terminal, and some
of the ganged connections make use of flat thin jump strips that allow the 2 additional
wires into those terminals. Each transmitter is connected between the 24 V supply and In+.
Each receiver is connected between the Out- and GND. Each Out+ must be connected
to 24 V, and each In- must be connected to GND, and the jump strips are used for these
connections.
Fig. 24
RIM10 terminal
24 V
Out 1 +
Out 2 +
Out 3 +
7
13
14
15
In 1 +
In 2 +
In 3 +
Out 1 -
Out 2 -
Out 3 -
In 3 -
GND
In 1 -
In 2 -
18
17
16
1
2
3
4
5
6
8
GND
GND
GND
4-20 mA
receiver
4-20 mA
receiver
4-20 mA
receiver
4-20 mA
transmitter
4-20 mA
transmitter
4-20 mA
transmitter
+ 24 V
+ 24 V
+ 24 V
4-20 mA
current loop inputs
4-20 mA
current loop outputs