Signal Cable Sizing for Analyser

[sijojoy]

Dear All,

I am having an installation of Ammonia analyser in a plant where the PLC is located 600 mtrs away form the instrument/ analyzer to be installed. The analyzer is working on 110V AC power supply & having analog signal 4-20 mA output and a Digital output FAULT ALARM.

Please help to size the signal cable in this scenario.

[sijojoy]

Nobody to give an advise???


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[qdzung]

It depends on your cables specification, you should contact your vendor to get the cable parameters.

For 110 VAC power supply, you should verify the voltage drop.
I think it's will be ok for analog (4-20mA) and Discrete status. (it's better to verify again)

I believe all such requirements are available in Project specifications.

[sijojoy]

Is there any online tool to size cables for dc voltage???


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[s.hassanjawad]

Dear Sijojoy,

- First of all, you need to specify that either the signal cable will be laid under ground or will it be laid overhead using cable trays? An important aspect is the classification of the area where this cable will be laid. Is it a hazardous area or not?

- For under-ground cables you have to use armored cable. As far as sizing of the cable is concerned, you can use 18-20 AWG (or 1 mm2) cables for both 24 Vdc signals (Analog & Digital).

- You can also use multicore cable in your case but harmonics of analog signal can affect the DI signal so it is better to use separate cables for these signals or you can also use a special purpose multicore cable that gives isolation b/t its pairs.

[s.hassanjawad]

Dear Sijojoy,

- First of all, you need to specify that either the signal cable will be laid under ground or will it be laid overhead using cable trays? An important aspect is the classification of the area where this cable will be laid. Is it a hazardous area or not?

- For under-ground cables you have to use armored cable. As far as sizing of the cable is concerned, you can use 18-20 AWG (or 1 mm2) cables for both 24 Vdc signals (Analog & Digital).

- You can also use muticore cable in your case but harmonics of analog signal can affect the DI cable so it is better to use separate cables for these sigals or you can also use special purpose multicore cable that gives isolation b/t its pairs.