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Author Topic: Need recommendation for geckos & BoB  (Read 4230 times)

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Offline Jackal

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Need recommendation for geckos & BoB
« on: November 18, 2010, 02:02:46 PM »
I have a Hurco Knee mill KM3p. After looking at every system imaginable, the Mach3 & Geckos keep coming up. Now it's time to buy!!!! ;D

My old servos are 90vdc and 12 amp continuous- 20 amp peak.

Which Geckos do I need for this? The 320, 320x ,or 340 ? I don't know enough about the different options to select one.They are on sale right now.

Also, The Break out Board. Which one???

CNC4PC, Bob Campbell, or Homann designs? Also which model? I've  read where ones  that have opto-isolaters won't work with certain Geckos, etc.

 I'll go with US encoders. Is there a preference for those? Do I need  differential type encoders or not?


I've checked with different companies they change  their products without changing manuals. You have to wait for a revision, or they don't reply for a week or 2 and you wonder how long they will be in business.

Geckos have been around a while, and people other than the factory can figure out the problems.

Same with Mach3, guys like Hood (among others) can set that up in their sleep. ;)

Thanks in advance,

JAckal
Everything is bio-degradable if you run over it enough with a lawnmower.

Offline Hood

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Re: Need recommendation for geckos & BoB
« Reply #1 on: November 18, 2010, 02:17:45 PM »
My preference for a BOB is the PMDX 122, no reason other than I have always used them and think they are top quality and I have never seen anyone have problems with them.

Regards the Geckos, afraid I have never used their servo drives but I would think if going Geckos it would be the latest(G320x)  which seemingly have a better PID on them

If your heart is not set on the Geckos then it might be worth looking at the Whale or its bigger brother the  Dugong from cncdrives.com , have seen good reports about them but again have never tried them.

US Digital are the usual encoders that people buy when they need reasonable priced encoders. Differential is not needed but it is preferred as it is more noise immune. The US Digital ones are single ended so you would need to get a line driver to make them differential and unless your drives can accept differential inputs (think Whale and Dugong can but dont think the Geckos can) you will also need a line receiver to change them back. Think the Dugong and Whale come with a line driver so you wouldnt need one if you went that route


Hood

Offline Hood

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Re: Need recommendation for geckos & BoB
« Reply #2 on: November 18, 2010, 02:26:21 PM »
Oh also meant to say if you are going with the Parallel Port then you dont want too high a line count on your encoders, 500 would be probably what most would use. If going with an external pulsing engine such as SmoothStepper then best go for a higher line count such as 2000.

Hood

Offline Jackal

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Re: Need recommendation for geckos & BoB
« Reply #3 on: November 19, 2010, 08:43:53 AM »
 Hood,

I really  don't  care for the Geckos, but there is so much support ( company and individual forum) and have been around a long time. Some of the drives  in the review by Simpson, seemed like they might not be around after a year or two. My drawbacks to Gecko is: the constant singing or dithering of the drives, plus an oscilloscope is recommended to tune them. 

Those Whale 3 drives  look like they are exact for what my machine needs. While tuning through a USB port with the company software appears ideal.

The Whales are less than  $120 US dollar each. I would like to get some feedback from some of the Whale users. Those RJ45 ethernet  plugs would be an easy hook up.

Thanks for the info,

Jackal
Everything is bio-degradable if you run over it enough with a lawnmower.

Offline Hood

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Re: Need recommendation for geckos & BoB
« Reply #4 on: November 19, 2010, 09:02:30 AM »
The new Geckos might be better in that respect but afraid I have no experience of DC servo drives other tan the contraves ones that came on the Beaver NC5 that I have. I was thinking of using them but when I first powered it up it was in the back of my workshop and I could hear the drives whistling away and I was standing working the lathe 40ft away. Drove me daft, or rather dafter ;D

Hood

Offline Jackal

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Re: Need recommendation for geckos & BoB
« Reply #5 on: November 19, 2010, 05:20:44 PM »
Hood,

Thanks for the info.

The factory drives on the Hurco whine until you home it out. It is aggravating (even with my bad hearing). ;D

If I am looking at it right, you could use a laptop with the tuning program to adjust the Whales through a USB port, and not even have to mess with anything on your control computer that is running Mach3.

 Is this correct, or just wishful thinking?

JAckal
Everything is bio-degradable if you run over it enough with a lawnmower.

Offline Hood

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Re: Need recommendation for geckos & BoB
« Reply #6 on: November 19, 2010, 06:24:58 PM »
I have not read the manual, will do in a bit, but that is the way my AC drives are set up so its likely the same with these.
Hood

Offline Hood

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Re: Need recommendation for geckos & BoB
« Reply #7 on: November 19, 2010, 07:03:49 PM »
Had a quick squint at the software docs and it looks like you can do the tuning from there.
Hood

Offline Jackal

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Re: Need recommendation for geckos & BoB
« Reply #8 on: November 20, 2010, 05:05:28 PM »
Hood,

I e-mailed CNC4PC last night and early this morning Arturo Duncan replied with some info about the Whale3 that he sales.  He has a Break out Board  (C32) that he recommends for this, with a couple of other mini boards between the drives and BoB. All of this will connect with regular computer network cables & plugs. ( RJ45 connectors).

After looking at the wiring diagrams for the CNC4PC, it looks easy. ::)  Almost as simple as connecting a phone and answering machine. ;D

What really impressed me about Mr Duncan, is the fact that he has e-mailed me twice (x2) on a Saturday.  Most places you can't get in touch with them during the week.

This system From CNC4pc is the first I have looked at that didn't intimidate me. His layout and wiring are for someone that isn't an electrical engineer.

Thanks for the info, Hood.

When I get ready to set up the Mach3, I'll be hollering for help.  ;)

Thanks,
JAckal
Everything is bio-degradable if you run over it enough with a lawnmower.