i want to connect the temperature transmitter (ABB) to the AI Module in RTU, what is the cable specifications required to that? from where can i get these cables? what is the maximum distance?

 

If your temperature transmitter is one of the 4-20mA variety any shielded twisted pair will do. The cable can be very long, it depends on the resistance and your power supply voltage. For 24 VDC the typical loop resistance is 600 Ohms. Allowing 250 Ohms for your RTU input module, that leaves 350 Ohms for the cable.

The transmitter specs will give you the formula for calculating the maximum loop resistance. Check the input impedance of your RTU, then calculate the maximum resistance of the cable.

Roy

 

The cable specifications choice depends on many factors: zone where the instrument has been installed, the way of cable routing, immunity noise ...ext. The shielded twisted pair cable is often used for petrochemical industries. For example, you can use NF M 87-202 standard.

For the Analog 4..20 ma the sensor can be installed up to 1000 feet away from its point of termination using a shielded, 18-20 gauge twisted pair cable and 24 VDC power supply. The total loop resistance should not exceed 900 ohms.

Regards.

 

Why do you do that? I think ABB transmitter should apply HART or other fieldbus. That is good to use, Why do you need to connect to AI module in RTU?

I think now all the AI modules support HART.