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Author Topic: Encoder connections to a servo drive instead of an encoder.  (Read 2721 times)

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I have a CSMIO/a which I have used in the past with no problems connected to conventional differential output encoders, now I am using it to drive 3 Panasonic AC servo drives which provide an encoder output. Now I encounter an error which says "check encoder connections" every time I start Mach3. If I close the message window and carry on it works fine but it will periodically reappear. I am guessing this may be because I do not have the power connections connected because they are not needed and that it senses that there is no power being consumed by the encoder and hence the error message. I have thought about fitting a load resistor across these connections but I have no idea what value would be needed.  If anybody out there could shed some light on this I would be most appreciative. Cheers Dave

Offline Davek0974

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Re: Encoder connections to a servo drive instead of an encoder.
« Reply #1 on: October 18, 2019, 03:48:17 AM »
Does it only appear when starting up?

My setup does this because the drives/encoders do not have a separate power supply, just the mains to the drive and this is not enabled until after the controller is up and running.

Better drives have a separate mains and control supply so the controls are up and on before the controller is then the main supply is enabled later.
Re: Encoder connections to a servo drive instead of an encoder.
« Reply #2 on: October 18, 2019, 12:33:04 PM »
I abandoned it altogether and went a different route, to answer your question the problem happened all the time even if the drives were powered up before the controller, I never did find out how the controller "sensed" the encoder, I assume it would be a current draw from the encoder. I thought about connecting it to the DRO scales but that can be problematic and the scales are single ended and would need a differential converter so I fitted another control instead (Fagor 8055m) which accepts different encoder inputs and by changing a parameter switches off the encoder sense, something CS-Labs should consider, otherwise they are a great controller. Cheers Dave

Offline Davek0974

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Re: Encoder connections to a servo drive instead of an encoder.
« Reply #3 on: October 18, 2019, 02:34:59 PM »
Thanks for the update.

Offline Hood

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Re: Encoder connections to a servo drive instead of an encoder.
« Reply #4 on: October 19, 2019, 01:38:48 PM »
The IP-A does not sense an encoder, it looks for the pulses and if it doesn't see them then it will error.
Sounds more like your drives outputs were either not suitable or you had them connected wrong.

Offline mark4

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Re: Encoder connections to a servo drive instead of an encoder.
« Reply #5 on: October 31, 2019, 12:48:30 AM »
On thing i just recently found on drives outputting encoder signals you need the 0v hooked between the drive and the controller. otherwise the ip/a has no reference as the circuit is not complete.