24v analog outputs FANUC R-J3

  • I'm trying to use the FANUC R-J3 to control the rotation speed of a old Vernon pipe processing table. It's my understanding that we might need another process I/O board. We want to use 24v to control the potentiometer of the Vernon table and to regulate the speed with various voltages. We are currently controlling it manually with the original Vernon potentiometer, but it's difficult to find the exact same spot on the dial (we need to change speeds for pipe in-feed purposes). Accurate rotation speed is crucial for programming the various cut-offs we need. Is there a way to seize control of the old potentiometer with analog robot I/O? I appreciate any instructions -


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  • Are you trying to physically turn the pot or trying to duplicate the 0-24v signal?

    You can buy pots with a motor that takes an analog signal and uses it to drive a motor attached to a pot. An example can be found at the link below. Disclaimer: I am not familiar with this companies products at all and have not used them myself.


    Alternatively you could use a digital potentiometer with standard digital I/O by using group output.

    I have also had success in building precise speed controlled rotary tables using Teknic ClearPath motors with their analog to frequency control board. The advantage with them is that they can be programmed via computer to control torque and acceleration response as well as act as a self contained servo.

    Hope this helps.


  • Hi Blade

    I'm trying to duplicate the 0-24v signals, and have the robot controller act as the potentiometer. We don't want to manually turn the pot, as there are various speeds needed and it would be great if each robot program could select them based on I/O. I see that FANUC R-J3iB has analog outputs of -10v to +10v and I wonder if that would control the FINCOR 2400MKII Model 2402, which supllies DC power to the table. Also, wonder what type of I/O cards for the robot would be needed.

    Thank you for the suggestions, links, and help!



  • Mark,

    Do you have an "A" cabinet or a "B" cabinet? Does it already have a backplane with I/O cards? One more thing, are you using an RJ3 controller or an RJ3iB controller?

    You will need and ADA02A card or if you want more resolution the ADA02B card. the difference is one is 12bit and the other is 14bit. These cards can supply either 0-20mA (my preference) or 0-10VDC depending on what terminals you use. You should be able to control the Fincor unit provided it has an analog input. It looks like some of them do but I'm having a hard time finding solid information. Do you have a users manual or a schematic of the current wiring of the potentiometer? Often these pots are wired as a simple voltage divider that effectively creates a 0-10v signal to the motor control.

    For the actual speed setting you will need to calculate the rpm to controller counts to analog signal yourself and write a program in the robot controller to do this conversion. If someone else knows how to apply scaling in the card configuration I would love to know how.

    I set up a turntable recently very similar to the one you are trying to do. I used a Macro to handle the conversion. I would call the macro with an argument (RPM). the macro took the number passed to it and ran it through an equation to determine the proper value for the analog channel to get the speed I wanted. I was using the 12bit card (ADA02A) outputting 0-20mA. I look up some of the details tomorrow for more info on the card behavior.



  • Blade,

    I have an RJ3iB controller with an "A" cabinet. It has a 2-slot backplane with some I/O cards. One card is an input card for a laser sensor and the other is an output for the plasma torch, which is controlled by RO[ ]. The pot is probably a simple voltage divider. We are using DO[ ] to turn the table ON/OFF.

    I'm searching for a Fincor 2400 MKII Model 2402 user's manual online, as we don't have one.

    I don't know too much about the Macro. In fact; I'm quite new to robotics, electrical wiring, etc. I was a forklift driver at a small manufacturing plant, the owner bought a robot and wanted to teach it how to cut pipe with a plasma torch. We had to hire a guy to come program it and he showed me how it worked, so I became the operator. Eventually i learned how to program it for other parts, so the owner bought another and we made it work, now I'm the programmer. I realized problems with the manual pot in regards to process repeatability. So now I'm investigating and learning fast as I can, which is a stretch for me. In terms of a career move, this is a great opportunity for me and I'm trying to make the most of it. I appreciate your patience.



  • I was going to suggest taking some measurements on the pot but, without doing testing on my own, I can't be confident that the motor controller would work like I expect. I would hate to give advise that could cause a malfunction and hurt someone and/or damage equipment. A picture of any of the labeled terminals on the motor controller could help in determining what options you have.

    You should have everything you need for adding analog out card. Before you do anything with adding I/O (or anything else for that matter) make sure you do an IMAGE backup. I learned this the hard way.

    Setting a program as a macro makes some minor changes to how other programs can call it and puts it into another category for easier sorting. It isn't something that is needed. It also lets you assign it to buttons and menus that can be run without being called from another program. I use macros to control things that are specific to a particular robot cell. I then call these macros for the main part programs. This lets me run the same program on multiple robots even if the cell setup is slightly different. I write protect the macros so they don't get deleted from the controller by accident.

    Hope this helps

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