DAC161S997: Current Loop Distance

Part Number: DAC161S997

Hi,

I had a customer wants to know on how much distance for the 4-20mA current loop transmitted for DAC161S997? Thanks.

Best Regards,

Ray Vincent

  • Ray,


    We don't have a maximum distance for the 4-20mA loop, but the resistance of the wire is important when designing for such a long length. The resistance of the wire must be low enough so that the voltage drop across the wire doesn't exceed the compliance voltage of the loop. The datasheet does have show an typical application in section 9.2. In that section, it also has some calculations on the compliance voltages in section 9.2.2.2 when there are other devices in the loop.

    Also in the typical application, a table describes the loop power supply for different loads and system wiring, going out to 2000ft.

    There may be other considerations with EMI and EMC. If the system and loop wire is well shielded, then the signal should be good for longer lengths.


    I would say that it is certainly good to 100m, but it should go much longer. I know of one tested system that ran out to 1km.


    Joseph Wu