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6-axes Robot Retrofits


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Has anybody been involved in Fanuc Robot retrofits using Unitronics PTO function?

I have a Fanuc Robot which due to a flat CPU battery lost its core program. It is really a mess trying to reinstall the software, besides the fact that you need the Fanuc people to do the job for you. What if you have a flat battery again?

I though of eliminating the original control, while keeping the Servo drives which should be driven by the Unitronics PTO function. Has anybody ever investigated this possibility, or has anybody ever made such an application? The 'one million dollar' question here is whether there is literature available on the Fanuc drives and what inputs these drives recognize. The rest is PLC programming.....

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  • MVP 2021

I just submitted an application note to Unitronics on this very topic. We're using the PTO function with Automation Direct servos (I know - :angry:) in stepper emulation mode. As long as you don't have to do circular interpolation, it works great. Post the model number of the Fanuc drives and I may be able to track something down.

Joe T.

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Dear Joe,

Thank you for your attention to the matter.

The Fanuc servo amplifiers on my robot (S-420FD) are the A06B-6066-H291, each driving two servos.

However, when you say stepper emulation mode you mean pulse train to drive the servos without feedback from the servo encoders - well I would expect this to be part of the drivers' job. I would be very surprised to see the Fanuc existing control to cater for encoder feedback from the servomotor encoders.

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The rest is PLC programming.....

No doubt talking to the drives is possible, but the rest of the PLC programming is going to be huge! I do a bit of programming on a 6 axis, and the "world" move feature always amazes me. You can perform RX and RY wrist movements and the tool tip stays in exactly the same spot! I get a headache just thinking about the trigonometry going on behind the scenes. Just doing a simple straight line move involves all 6 servo's...

Good luck- I would pay good money to see the code!

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Has anybody been involved in Fanuc Robot retrofits using Unitronics PTO function?

I have a Fanuc Robot which due to a flat CPU battery lost its core program. It is really a mess trying to reinstall the software, besides the fact that you need the Fanuc people to do the job for you. What if you have a flat battery again?

I though of eliminating the original control, while keeping the Servo drives which should be driven by the Unitronics PTO function. Has anybody ever investigated this possibility, or has anybody ever made such an application? The 'one million dollar' question here is whether there is literature available on the Fanuc drives and what inputs these drives recognize. The rest is PLC programming.....

I agree with Ziwi. This is a huge undertaking and I'm not sure the UNI is suited for that type of control.

I use fanuc robots, and everything is well documented. However, the don't make the documentation very accessible to just anyone. I am on their integrator program and it is still like pulling teeth to get some information.

D

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You'll have to evaluate your application to decide if it's worth trying to write your own motion control program. If you need to work in virtual X and Y coordinates as opposed to absolute positions then you will have some pretty intense calculations and you may well run out of floating point registers in Unitronics. That's not to say it can't be done.

The application we did was a single axis high precision feeder that wasn't too complex from a motion standpoint.

Here's a link to the maintenance manual-

Alpha series manual

The manual mentions some kind of screen. Is there a monitor port on the amplifier, and do you have it? Or does it use an RS232 terminal?

Joe T.

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