AAD04A Analog Input Card Refresh Rate

  • I am having an interesting issue where the analog input is updating extremely slowly. I have a laser sensor that outputs 0-10V, this signal wire is landed on V+, the V- has the same ground that the sensor is using and com and v- are connected.

    I can see on the multimeter the sensor output switch from 0 -> 10V instantly but on the card it's updating at about 35/sec (0-600, respective to my 0-10V).

    Anyone have any idea why my refresh rate would be so slow?

    It's on a R30iB controller.

  • AD
  • According to the specs, the input filter delay on that card is 50ms, or 20Hz. Sounds like you are doing a bit better than that.


    If you need speed, you will have to buy an AAD04B2 module. It runs at 500Hz.

    Check out the Fanuc position converter I wrote here!

  • What I mean by 35/sec is I can watch the analog input slowly climb till it maxes out. If I switch the input from 0V to 10V instantly, the input goes from 0-600, but not instantly, it takes about 20seconds. And similarly when switching from 10V to 0V.

    I thought that it takes in whatever voltage it's getting and converts that to an output, and would do this conversion at 20HZ?

  • HawkME, I mean the analog value is changing at 35/sec. When I switch the voltage from 0->10 the analog value after 1 second is around 35, not at 600 like it is after I let it settle for ~20sec.

    Nation, I just checked and they are the same.

  • That sounds a lot like a large capacitance on the line somewhere. I would suggest putting a high-impedance meter directly on the input contacts of the analog card (not at a distance along the input line), and monitor the voltage change there. Or plug a reference test voltage directly into the analog input card with a short, clean pair of wires.


    If the analog card response is still laggard even with the input line eliminated, the card may be suspect.

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