Models 375-31H Area Monitor with Neutron Detector
Section 5
Ludlum Measurements, Inc.
Page 5-8 January 2021
4 to 20 mA Isolated Output Driver Option
4 to 20 mA Driver (Isolated) Modification Kit Part Number 4558-104
This circuit may be added to replace the Model 375-31H analog output,
providing an isolated 4 to 20 mA output capability.
The circuit has an internal loop supply, generating +12 Vdc from the
RAWDC of the Model 375-31H. It is designed for a 2-wire configuration,
with one conductor carrying the 4-20 mA current signal and the second
conductor providing a return (isolated loop ground). See Wiring Diagram,
Figure 4 (below).
Figure 4: Wiring Diagram.
Decade
“Base” Display
mA Value
0
0.1
4 mA
1
1
7.2 mA
2
10
10.4 mA
3
100
13.6 mA
4
1000
16.8 mA
5
10,000
20 mA
5396-754
