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Author Topic: Problem with the length of motor and encoders cable  (Read 4092 times)

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Offline Robhi

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Problem with the length of motor and encoders cable
« on: August 25, 2013, 11:55:34 AM »
Hello every body,

I have nearly finished my machine cnc mill, but I have a problem with, I guess the encoders,

Motor:- KL34-180-90
Encoder:- Am 102 Digi-key 500 lines.
Power supply : 65 - 70 volt dc.
Gecko 320x
When I tisted all, motors etc.. with short cables , every thing was ok and motors run very fines. but, when I mounted them on the machine, every thing changed:-

motors do not accelerate very well, that means they take time to accelerate . times of responde is( very long)
and also when they stop, they do stop as before, they contiue to move 1 or 2 seconds.

enocder and motor have long cable, may be more than 5 meters for z and Y..

Could I have your help please?

Thanks a lot

Robhi
Re: Problem with the length of motor and encoders cable
« Reply #1 on: August 25, 2013, 12:09:29 PM »
Cable length is not a problem - mine are over 20 feet, and work perfectly.  How did you tune ther servos?  Sounds like they are massively out of tune, and runing CANNOT be done on the bench - it much be done on the machine, under load.

Regards,
Ray L.
Regards,
Ray L.

Offline Robhi

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Re: Problem with the length of motor and encoders cable
« Reply #2 on: August 25, 2013, 12:25:51 PM »
hi,
thanks for reply,

Whwn I tunded them without load, they worked perfectely, but tody when I mounted them on the mychine, I tried to move them  without any load, only the length of cable changed, I noticed that they are not ase before. I used not shielded cable for the encoders may this is the problem?

thanks
Robhi
Re: Problem with the length of motor and encoders cable
« Reply #3 on: August 25, 2013, 12:40:05 PM »
Tuning on the bench will NOT work!  If you did not re-tune them after mounting on the machine, there is no reason to expect them to work properly.  Yes, you should use shielded cable for the encoders, with the shield connected only at the G320X.  Also, USDigital encoders are less than ideal for the G320X, and will require disabling the encoder failure detection in the G320X.  AMT encoders are MUCH preferred.  Do you have switch 6 on the G320X set to ON?  If not, they will work very poorly with those encoders.

Regards,
Ray L.
Regards,
Ray L.

Offline Robhi

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Re: Problem with the length of motor and encoders cable
« Reply #4 on: August 25, 2013, 02:50:24 PM »
Ok, I am sure you are right... I will do so next week end.. and of course change the cable of the encouder.

Sure also that the switch 6 on my gecko is off , will change too... but you say that I have to connect the shiel only at the gecko. How to do so? connect it to the body, itself of gecko? coould you tell me how to do so please?

thanks again and will tell you next week of course..

thanks

Robhi
Re: Problem with the length of motor and encoders cable
« Reply #5 on: August 25, 2013, 04:05:45 PM »
Connect the encoder cable shield to the ENC- pin on the Gecko.

If you had switch 6 off, it's a miracle it worked at all on the bench.

Regards,
Ray L.
Regards,
Ray L.

Offline Robhi

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Re: Problem with the length of motor and encoders cable
« Reply #6 on: August 25, 2013, 04:28:39 PM »
I have a look at gecko manual, I found that there are only to ENC pin, the first is ENC ground the second is ENC 5VDC.
is it one of thèses pins you are tellimg me?

thanks

Robhi
Re: Problem with the length of motor and encoders cable
« Reply #7 on: August 25, 2013, 07:43:10 PM »
I have a look at gecko manual, I found that there are only to ENC pin, the first is ENC ground the second is ENC 5VDC.
is it one of thèses pins you are tellimg me?

thanks

Robhi

ENC Gnd.
Regards,
Ray L.

Offline Robhi

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Re: Problem with the length of motor and encoders cable
« Reply #8 on: August 26, 2013, 02:59:53 PM »
Ok thanks too much..


I will do all theses steps and let you know

thanks again

Robhi

Offline Robhi

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Re: Problem with the length of motor and encoders cable
« Reply #9 on: August 31, 2013, 05:20:57 PM »
Hi ray,

I have made the changes as you told me, but I still have some noise only with the y axis. I have wired all four motors the same way, x,y,z and slave one. everything is ok but not the y one, any help please?

thanks in advace

Robhi