NEP-9500 MANUAL V1.01
Observator Instruments V1.01
Copyright 2017
©
Page 11
4-20mA Current Output version
ANALITE NEP-9500 probes may have an analogue 4-20 current output with a
maximum load rating of 50 ohms, consequently cable loop resistance should be taken
into account. The PUR cable normally supplied with the probes has a nominal loop
resistance of 4.6 ohms per 100m. A schematic of the probe and its load is shown
below.
For very long cable runs (>200m), it may be advisable to connect the NTU Return conductor to the
Supply Common conductor at the end of the cable to reduce the voltage drop along the run.
When a NEP-9500 series probe is ordered with the 4-20mA current output, the probe is configured
as a (high) current source. The load must be less than 270 ohms to ensure proper operation over
the probe’s specified power supply range.
Wire color
Current option
Green
Ground (0V Common)
Shield
Shield (No connection within probe)
Brown
8 to 30V DC power supply (+ve)
Grey
Wiper (Probe sleep/Wipe)
Yellow
NTU
Current
Common
White
NTU
Current
Output
