[?]: connect 4-20 m to ABB analog input module AI801

[omar zedan]

Dear All
I have AI801 analog input module(8 channel) in my rack and when i use AVO meter to read voltage between + and - for each signal I read 24Vdc, my signals are 4-20 mA how can I connect my input to this channels??? (Must I use safety barrier ????)
Note:- I set the input as 4-20 mA in software.
Note:- I mean Can I set this module as a sink (not source)????
Thanks for all

[Linkinx64]

24V is service voltage, it's always like this for all low voltage IO.
But load resistance is different.
So, if the module is not reconfigurable as INPUT/OUTPUT (when you can set module terminal in software as IN or OUT) - no you can't connect power consuming device to the analog input.
Possibly the device will not work or fuse on module inputs (actually, outputs in your situation) will burn out.

[omar zedan]

Dear Linkinx64
I do not fully understand you,
I have (controller, digital input module DI801, digital output module DO801 and analog input module AI801)the problem in analog input module is that I have four wire flow meter (2 wires for power and 2 wires for return signal (4-20 mA)) and I afraid from connecting the 2 wires of signals to the module because I find 24 Vdc in the channel of analog input module.
Note:-I connected power 24Vdc to the module.
What can I do to remove 24 volt from analog input module channels to make AI801 module read 4-20 mA from external device????
Thanks

[Linkinx64]

There are 2 inputs for each of channels as far as I know: one is N+ (where N - is a number of channel) another is NI (current input).
Each of N+ is connected to the L+ (24V DC). So how many volts do you expect to measure between N+ and NI if not 24?

[vk+1234]

Hi,
If You have 2 wires 4-20mA sensor, which gets power from 4-20mA signal, simply connect +pin of sensor to N+ (directly or thru 63mA fuse) and -pin to NI. That's all
If Your 4-20mA sensor has 4 wires - active type, then You must connect 4-20mA signal +wire to NI input and signal -wire to module ground, which is L-24V power pin. Usually, if sensor obtains power from the same 24V power supply, You need galvanic isolation device for connection to work properly, or power the sensor from own, floating power supply.

[omar zedan]

Hi
I fully understand you, but my problem is:-
I have (8 channel) AI801 analog input module.
before connecting Analog input:-
I musear the voltage between N+ and N- (where N may be any Channel from 1-->8) and it will be 24Vdc (the channels are source).
therefore I cannot connect my signal to this channel because my signal is 4-20 mA and my signals has its own power supply(4 wire transmiters).
Note:- I have in compact control builder AC800M software in hardware config. in setting tab a parameter called Activate channel1....Activate channel2......Activate channel3.............................Activate channel8 and the value of this parameters are true.
dose this mean if I chose false to this parameter I will make the channel as a sink??????
Thank you