Monroe Electronics Electrostatic Fieldmeter - Static Monitor - model 177A - Manual (Page 31)

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Section 11
Optional 4 – 20 mA Module
General
The optional 4-20 mA module provides 4 separate channel outputs in addition to the normal voltage
outputs. All channels have a common ground. The instrument provides a 12-volt nominal supply
which gives a compliance range of 7-volts. No external supply is required provided the 7-volt
compliance is observed.
An external supply may be connected which would be used by all four channels. The external supply
must be less than 25-volts. Output compliance of the is the external supply minus 5-volts. Note that
this supply will be referenced to chassis and analog ground.
A termination resistor must be installed on the 4-20 mA receiving equipment and must be less than
the compliance voltage, or
V
complaince
> .020 *R
in
where R
in
is the receiver input resistance
Specifications
Internal Supply: 11 volts min
External Supply: 24 volts max