Wells Index Analog Amplifiers, DC Permanent Magnet servo W/Tach, Resolvers...

@riversvic,

Not a problem, was hoping to help in any way possible as I know how it is to waste time trying to find info.

I actually went back and re-read about resolvers as it had peaked my curiosity to refresh on them. They are super reliable, but not as good of feedback as encoders for the time period back then. It does look like some newer resolvers actually outperform encoders in todays world, but this is military space grade parts... not affordable to me LOL.

I did not check out the model number to the Electro-Craft motors you have, but I do have some info for the one's that I have if you run into a dead end.

Hope the retrofit is easy and goes well, as there is no better feeling than finishing and running the machine.


Robert

So initially when I was forcing power to the machine I was doing it in an unsafe manner. I now applied ac in a safer way and discovered that all 3 axis are drifting slowly when I turn the machine on. I did not notice This before because the position I was in when forcing power.

I think i said this before, but just in case, the drifting is normal when the inputs are not connected to the controller, and they should NOT be zeroed.

Tom is correct, since the controller is not fired up and giving commands to the servo amps then they are simply operating with no input to offset the output from the amps. In other words, since you do not have the controller operating totally the whole system from computer/mesa board sending analog output to the amps sending power to the servos moving the resolvers to send feedback to the controller loop is missing. In other words the hardware loop is open since you are missing the computer to tell the amps what to do, is not tied together and therefore is why you are just drifting when fired up. You may be able to understand it this way, the output from LCNC is to offset what is happening downstream of the amps and since there is no LCNC to give the offset then the amps are giving a very small output and the servos are drifting. That is normal and ok, once you install a computer with LCNC and hook everything together on the mesa board, that will close the loop in your hardware. COMPUTER/LCNC to MESA to AMPS to SERVO moves RESOLVER feedback goes back to LCNC through mesa board... completes the loop

So you don't get confused, there are 2 loops. The hardware itself and then in the software when using LCNC, so you are technically open in both loops. You can put all of the hardware together and have the hardware loop closed, but since the software is not there to tell the amps what to do, your loop is open on the software also.


Hope this helps clarify.

Robert

riversvic wrote: For the 750 I am leaning towards removing the analog amps and going to a step and direction system and swaping the resolvers to encoders. I have a friend at Rockwell looking into the Electrocrafts for some specs on them.

Resolvers work fine, and are tougher than encoders.

I have been known to remove an encoder from a motor and fit a resolver.

A Mesa 7i49 is all you need to interface the resolvers and control the analogue amps.

@riversvic

There is the answer you needed... If Andy says they work then they do.

I just haven't ever messed with them in the past, but that would be the easiest way. You simply interface with the Mesa board and you will be up and running quicker than changing everything out, much easier than the hardware change, plus cheaper.

I believe you are closer than you think on getting it running.