[tindur87]

What length of cable can I use to connect the CUI AMT102-V to the G320X servo drive ?

[Bob La Londe]

6' shoud be no problem at all.

You can probably more than double that if:
1. Use a larger conductor. 18 ga is pretty big. 16 won't even fit in the terminals.
2. Use a shield and bond the shield at your common ground point.
3. Use only a high enough resoltuion to do the job.
4. Follow good wiring practices and follow good shielding for all of your wiring for everything.

I have one Gecko servo controllers working with USDigital E600 at apx 13' wire length, however as I have found out after a couple retrofit projects nothing is guaranteed to work in every environment.

[tindur87]

Thanks for the reply. Would something like this http://cncdrive.com/downloads/Diff_l...ver_manual.pdf work as a direct "bolt on" to extend the run length for the wires ?

[Bob La Londe]

No. That's for converting singled ended encoder outputs to connect to a driver that wants differential inputs. A G320X is expecting singled ended inputs from the encoder.

What kind of range do you need?

[tindur87]

Around 30' if I keep my setup the way it is now

[Al_The_Man]

You would have been better off maybe with the differential version and fitted a Diff to single ended convertor at the Gecko end.
I never know why all drive manuf do not incorporate the near universal differential input?
Al.

[Bob La Londe]

From what I have read that's going to take good quality cables, good noise reduction techniques, and a differential encoder. You can then use a differential to single ended adaptor at the servo controller, or find a servo encoder that is expecting differential inputs. Also, power is going to be an issue. You want to make sure you have an adequate current power supply for your encoders so that you don't get any voltage drop. If you go with an 18 gage wire you shouldn't have any problem with wire resistance drop at only 30'. On the other hand the AMT encoder is such a good price you can always just try it and see.

Why do you need 30' from the servo controller to the encoder? If its because you have the controller across the room move it. If its because you have a huge router then put the controller at the mid point of the bed. It will save some wire length and a few other things as well. Like drag chain. Also, if you are running a VFD controlled spindle distance there can be an issue.

[Bob La Londe]

You would have been better off maybe with the differential version and fitted a Diff to single ended convertor at the Gecko end.
I never know why all drive manuf do not incorporate the near universal differential input?
Al.

Price. Its pretty hard to beat the price of a Gecko controller if it will work for your application. I know. I know. We can argue about what it would actually cost to add, but the reality is it doesn't always just cost "what it costs" to add something or incorporate an additional feature.

[Al_The_Man]

I design a lot of my own stuff, it would not seem all that costly to add a differential receiver, there has to be a receiving IC of some kind anyway.
And the this would essentially be an attractive added selling feature IMO?
Al.

[Bob La Londe]

I design a lot of my own stuff, it would not seem all that costly to add a differential receiver, there has to be a receiving IC of some kind anyway.
And the this would essentially be an attractive added selling feature IMO?
Al.

I guess that would be a questions for one of the Ms. Their controller does work, but the next attractive controller to me is twice the price. Maybe an extra 100-150 per isn't that bad, but its something a DIY builder or a hobbyist has to watch. All those extra, "its only another hundreds." They add up quick.

Anyway, if we could only use the perfect"est" solution for everything then we would have died out as a species with Fulsom man, because nobody would have ever found just exactly the best rock to make a spear point, and the sabertooth tigers would have eaten us all.

More specifically, adding a single component might be cheap considered by itself but what if the circuit board has to be a few mm wider? New circuit board. New board production and assembley process, new cover... they all add to the cost. Not counting the initial cost to figure it all out. I'm not saying you are wrong. Just that there is always more to it.

[Bob La Londe]

To the original poster, we do seem to agree that a differential encoder is the best answer for your distance issue. From there its upto you ultimately to find the most cost effective solution that works for you to turn cumputer control into machine control.

If cost is an over riding factor then you certainly need to see what you can to minimize wire length in your layout and design.

[tindur87]

Yeah tell me about all the extra dollars here and there they sure do add up, but what differential encoder would you recommend for use with the G320X ? Would be great if you could send me a link to a retailer with the encoder and whatever else I would need to make it function with my motors

Thank you for the information

[Al_The_Man]

The I.C. itself is 70¢ in qty?
CUI can be purchased with the differential option.
Al.

[Bob La Londe]

The I.C. itself is 70¢ in qty?
CUI can be purchased with the differential option.
Al.

Will you design the circuit to add it, and provide everything else required for free? Will you make it backwards compatible for single ended encoders, so everybody doesn't have to throw them away. Will you provide differential encoders for the same price as an AMT 102? Are you enjoying the discusion or do you not understand that a 70¢ part doesn't cost 70¢ installed.

To the OP, a USD E5 will probably work for you just fine. The E6 also works (and its what I am using). They are both available in differential or single ended. You just plug in the features you want on their website, and they send it to you. At a quick glance the peak current of both is higher than the supply from a G320X, so an external power supply for them might be required. I am using E6s (single ended) off the G320x and they seem to be working ok. Good design would be to provide adequate power for peak demand. Especially considering your extreme application.

Sorry, I do not have a good suggestion for a differential to single ended adaptor, but Al_The_Man can build you one for 70¢. (LOL)

[Bob La Londe]

I hesitate to mention it since you sound like you already have the G320Xs, and this is the Gecko board, but Larkin's Viper 200 (his most sold controller I believe) has support for differential encoders. I almost went with them myself, but for voltage and current reasons. Not differential support. I selected the Geckos because of price and designed the rest of my machine controls around them to the best of my ability. I think if he had his tuning software available at the time I purchased my Geckos I might have gone that way instead. Still, the G320X is a pretty good control for the price.

[Al_The_Man]

Yeah tell me about all the extra dollars here and there they sure do add up, but what differential encoder would you recommend for use with the G320X ? Would be great if you could send me a link to a retailer with the encoder and whatever else I would need to make it function with my motors

Tindur87

CUI encoders are available with the differential output ver 102-xxxx-E-10 but they may be difficult to find, another low cost source of differential encoders is US Digital.
It is very simple to put together a diff to single end receiver, I have had to do this a few times in the past, if you need a schematic at all I could send it via P.M. just a couple of components.
Al.

[Bob La Londe]

Looks like Arturo at CNC4PC has a differential to single ended adapter pretty cheap. CNC4PC

I have a C23 breakout board from him, and I had to repair a cold solder joint on one of the pins (estop I think), so bare that in mind. I have also heard a few other complaints about some of his stuff. Still, cheap is cheap. Buy a couple extras just in case.

[tindur87]

So I might be able to combine the single to differential at the encoder side with the differential to single adapter at the gecko to enable longer cable runs ? They are cheap at least

[Bob La Londe]

I don't know about that. I don't think the adapters are really intended to be used that way. I don't have any way to quantify it, but that just doesn't "feel" right to me. I think it just gives you a single end application with more stuff in the middle to go bad.

[Al_The_Man]

So I might be able to combine the single to differential at the encoder side with the differential to single adapter at the gecko to enable longer cable runs ? They are cheap at least

If you keep the current encoder, you would need the RS485 single ended to differential convertor at the encoder and the reverse at the Gecko end.
Actually the CNC4PC site show it.
Al.