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use 24VDC 4-20mA + 2.5VDC Potentiometer in CR1000X will damage my instruments?


chalit May 26, 2022 12:57 AM

Hi,

I have one CR1000X, 4-20mA sensor (require 24VDC) and Potentiometer (excite voltage from VX1 terminal of CR1000X)

they use the same G terminal of CR1000X, can i use them together ? 

Different in voltage of these sensor will damaged my logger/sensor or make measurement error ?

note:

- Use 12V input to 24V output, DC to DC converter to powered 2 wire 4-20mA sensor

 power from SW12 from CR1000X


smile May 26, 2022 04:49 AM

it's a common situation. Many 2-wire sensors with 4..20mA output use the 24V supply voltage.

Often, however, these probes have a wide input power range, so check if it can also work up at 10V (battery voltage of the logger, minus 2 V that you can lose on the 100 Ohm resistor in the maximum value of 20mA)

I recommend using a precision resistor and stable in temperature, at 100 Ohm. CS has terminals already prepared for this, for example CURS100.

Connect the resistance in series on the negative lead of the probe and you can make a single wire or differential measurement.

The SchortCut CS program offers valuable help.

There would also be the possibility of using an internal resistance to the logger.

I am not convinced to use the G with a potentiometer, the negative of the Vx is better to use the terminals with the earth or ground symbol.

The G is the return of the 5V or 12V power supplies of the logger and reference of the digital channels, many other functions but not the return from the VX excitations

the connection diagrams, in short cut, facilitate the explanation

Smile


chalit May 26, 2022 06:36 AM

Thank you for your advise.

1) this 4-20mA sensor accept only 24VDC

2) so, Potentiometer connect to VX1, analog groud and SE channel.

and

4-20mA sensor connect to CURS100, 24V and G

The wiring like above shall not damaged my logger/sensor or make measurement error?

Regard,

Chalit I

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