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Author Topic: servo drives and ecoders  (Read 5588 times)

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servo drives and ecoders
« on: October 06, 2013, 02:03:25 PM »
in using Omron R7M  drives to convert my Hurco and need to connect the encoders , the encoders on the HURCO motors are 6 pairs plus 0v and 5v , but there are feedback encoders fitted to the ball screws on each axis that have A+,A-,B+,B-,GZ+ and GZ- so im thinking of using these connected to my servo drives , the drives have the A,B and a Z connections but also have a S+ and S- ? do these need to be used ? if so what are they for ? appreciate any advice

Jamie

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Re: servo drives and ecoders
« Reply #1 on: October 06, 2013, 02:38:10 PM »
You will need to use motors/encoders that are suitable for the drives you have, I think the Omrons will be AC Servo drives.
Are the motors you have  AC  or DC Servos? Sounds like they are DC Servos due to the lack of commutation signals
Hood
Re: servo drives and ecoders
« Reply #2 on: October 06, 2013, 02:46:24 PM »
the motors on the machine are  AC servo motors , , three phase 200v , but the original encoders have PA, PA+,PB,PB+,PC,PC+,PU,PU+,PV,PV+,PW,PW+ as well as the  5V and 0V  ( plus the separate 3 phase power supply to the motor) so I thought I might be able to use the feedback encoders and retain the original motor from the machine?

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Re: servo drives and ecoders
« Reply #3 on: October 06, 2013, 02:50:00 PM »
Ok so the PU, PV and PW are the commutation signals for the motors.
I am not sure what the Omrons require as some modern AC Servo drives do not need commutation signals. Do you have a link to the manual for the drives you have?

Hood
Re: servo drives and ecoders
« Reply #4 on: October 06, 2013, 02:57:21 PM »
I have attached the manual Hood , if you can have a look and see if its going to work otherwise i need to find new drives or motors? just would be handy if I can use what I have ,  I went with the CSMIO control after your advice , nice piece of kit (only thing is I bought the step/dir one as I had these drive so its a shame if they wont work ) oh well :)

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Re: servo drives and ecoders
« Reply #5 on: October 06, 2013, 03:08:10 PM »
Ok on pg 55 it shows the CN2 connections and there is no mention of commutation, so it looks like these drives sense the commutation  themselves and dont need feedback from the encoder.
 I am not sure if they will work or not with your current motors but likely they will as long as the signal  types are the same. The manual seems to suggest that it is ttl signals and that is likely what your motors encoders are.
Are the motors voltages and currents within the specs of the Omron drives?
Hood

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Re: servo drives and ecoders
« Reply #6 on: October 06, 2013, 03:14:59 PM »
Also better make it clear that matching AC drives and motors is not nearly as easy as matching DC brushless motors and drives.
AC Drives usually require you to have all the info entered for the motor, such as voltage, current, inertia etc. Some drives will not allow you to enter that except for standard motors that match the drives, others allow you to set up a custom motor profile and the newest ones tend to use "smart" encoders that have that info in the encoder.

Hood
Re: servo drives and ecoders
« Reply #7 on: October 06, 2013, 03:16:28 PM »
Yes the motors are 200v  3phase  750w motors , I'm thinking of using the feedback encoders off the ball screws as they have A+ ,A-, B+B-,,GZ+GZ- and if you look at CN1 there's a  pair of Zphase connections , am I wrong I'm thinking that's my GZ phase ?

Re: servo drives and ecoders
« Reply #8 on: October 06, 2013, 03:17:36 PM »
Oh so it may not be so simple !

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Re: servo drives and ecoders
« Reply #9 on: October 06, 2013, 04:06:31 PM »
These signals on CN1 will be outputs, ie for passing on the index signal to other hardware, possibly for use in Index homing.

Hood