Setting up Analog Input

    We are in the planning stages of an upcoming project. No one in our office has any experience using analog sensors with the Fanuc robots. We will be holding onto a part with a hex on it that needs to be oriented. We will clamp onto the part and then rotate the part with the robot. We want to setup some sort of analog sensor to work with the robot, presumably via EthernetIP, to monitor the hex while the robot is rotating the part. It would rotate the part until it finds the high(or low) spot, stopping, and then backing up to the high spot. Here are some of my questions:
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    • Any suggestions about what brand or kind of analog sensor to use for this application?

    • What about connecting/configuring the sensor, any pointers or things to worry about? Also is EthernetIP the way to go?

    • Anyone got any example code? We have talked about setting a R[1] based on initial position, begin rotating part, putting that new position into R[2] and comparing that to R[1] and putting the difference into R[3]. The difference would rise, but at some point it would stop rising and we would need to stop and then back up to make sure we didnt overshoot. I am explaining it crudely, but does this sound like I am on the right track? Is there a simpler method?

    • This whole concept revolves around being able to quickly and repetitively capture a position and then comparing it to another position while the part is in motion, is it probably best to try to run this in a background program? Or will setting up a loop of some sort in my TP program work just fine?

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    Thanks in advance for any help or guidance.

    I would use fanuc model A i/o. I have tried using ethernet i/p for analog signals before, but there was too much variability in the timing. Model A is much more repeatable than ethernet i/p. A deterministic network such as control net would work better, but I doubt you would want go back in time to use it.
    Fanuc does make a 16-bit input card, but they do not sell it, or at least they didn't the last time I tried to buy one. Because of this, you get stuck with a 12-bit card, which can limit your resolution, but if you scale your signal properly, you should be okay.

    -Phil

    Edited once, last by pdl (January 5, 2018 at 1:00 AM).

    You could use EIP for that, just be sure that the sensor (or the module) you are planning to use is compatible with the controller.
    For example, I've worked with Weglor 32-bit laser distance sensors connected directly via EIP, BUT the configuration required some assistance from Fanuc, because the configuration form on the TP did not allow to set all the required parameters. Fanuc's support has used some Allen-Bradley software to get the proper parameter values and then set them directly in system variables. After that, the sensor worked like charm.

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