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4-20mA circuit issue

Pscamm Feb 28, 2024 05:05 PM

Hello all,

Have a strange one here.....

We have a water meter in the form of a clamp-on fitted to the pipe and a controller which is putting out a 4-20mA channel for our CR800 logger to record the water flow rate.

The resistor bridging 1H to 1L burned out causing a NAN on the Logger.Net Table 1 screen. I later find out that this controller is putting out a 4-20mA signal at 24v, does not have an option for an active or passive loop and has no option to change to 12v which our logger would be happy with.

So we are stuck with 24v. How do you deal with a 4-20mA / 24v loop on a CR800 logger, surely there must be a way to reduce that voltage without affecting the current value.  ? ? ? ?

Any help would be gratefully appreciated.

Many Thanks


trevisscot Mar 24, 2024 08:24 PM

This post is under review.

smile Apr 2, 2024 04:19 PM


The 24V issue is only related to the probe, it cannot affect the logger. Is the 24V negative common with the 12V negative that powers the logger? do you have a precision 100 OHM resistor to convert the 4...20mA signal into 400.....2000mV voltage? CS can provide the specific CURS100 for this activity. Is the probe 2-wire or 4-wire? Do you have manufacturer and model? If the resistor has burned out you have used the wrong connection. Have you tried the pattern that creates the SHORT CUT?


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