How to reverse DC drive without a reverse pin?

[frijoli]

I was slightly misinformed about the drive I have and it's control.
I have a KBMG and an SIMG isolation board. I was told that all I needed to do to reverse the direction was to reverse the polarity on the analog input. In reality I need to invert the polarity.
Meaning instead of 0 to +10vdc, I need 0 to -10vdc. This I do not know how to do without special boards.

Does anyone know how to do this simply or should I dig around for different drive?

[frijoli]

I was slightly misinformed about the drive I have and it's control.
I have a KBMG and an SIMG isolation board. I was told that all I needed to do to reverse the direction was to reverse the polarity on the analog input. In reality I need to invert the polarity.
Meaning instead of 0 to +10vdc, I need 0 to -10vdc. This I do not know how to do without special boards.

Does anyone know how to do this simply or should I dig around for different drive?

Quoting my own post, I have an different version of this question: Can I reverse the output? It seems way more kludgy...

[DICKEYBIRD]

Do you mean the KB drive's input signal needs to be +/-10vdc? I don't think you can do it without using up an Acorn output to switch the 0-10v Acorn output's polarity with a DPDT relay. (Silly me, you knew that already.) Maybe one of the gurus has a way?? That PLC is magic in the right person's hands!

[frijoli]

Do you mean the KB drive's input signal needs to be +/-10vdc? I don't think you can do it without using up an Acorn output to switch the 0-10v Acorn output's polarity with a DPDT relay. (Silly me, you knew that already.) Maybe one of the gurus has a way?? That PLC is magic in the right person's hands!

Yes, it has to be plus or minus 10vdc. Not the same as changing polarity. I could do it with an OP AMP and make a circuit, but I'd rather do this with off the shelf parts.

[martyscncgarage]

Do you mean the KB drive's input signal needs to be +/-10vdc? I don't think you can do it without using up an Acorn output to switch the 0-10v Acorn output's polarity with a DPDT relay. (Silly me, you knew that already.) Maybe one of the gurus has a way?? That PLC is magic in the right person's hands!

Yes, it has to be plus or minus 10vdc. Not the same as changing polarity. I could do it with an OP AMP and make a circuit, but I'd rather do this with off the shelf parts.

Yeah, well, I suggested that to the boyz at Centroid, that the Acorn have the SAME spindle control as the OAK and All in One DC which indeed allows +/-
0-10VDC. I got shot down, hitting the ground in flames.

I hope a future hardware revision has this feature. (Fingers crossed, would make things so much easier and consistent with the product line.)

I did create a small board that does just as you describe. Without the reverse signal input, it is 0-10VDC, when it gets the reverse signal input, it flops to -0-10VDC. Its fairly simple. It does require a power supply with +12VDC and -12VDC.

Frijoli, I would make the board and roll with it. The KBMG uses industry standard +/- 0-10VDC,
I think you will need a relay to open and close the inhibit input on the KBMG when the spindle is commanded on. I think you could use the spindle brake output for this...

Marty

[DICKEYBIRD]

Yes, it has to be plus or minus 10vdc. Not the same as changing polarity.

Now that there is something I don't understand. I have an AMC servo drive I plan to install on my spindle some day and it's controlled by your magic +/- 10vdc. So you guys are saying I won't be able to control it with the analog 0-10vdc signal running through a simple DPDT polarity reversing relay circuit? 'Splain it to me Lucy.

[martyscncgarage]

This whole thing joggled my memory. I have a Dyna Myte DM4400 mill with ATC
Crap load of pictures of this project here:
https://goo.gl/photos/neSAL3iVeFEAtjTRA

It has a large DC Brush Servo for a spindle motor and a Servo Dynamics analog amplifier that takes =/- 0-10VDC standard analog input. I tried the relay thing and it did not work. It had to see a negative voltage. So with the help of several friends, designed a small board that did what I needed and still works today...

The board is pretty simple as I explained previously.

Like I also said, SADLY, Centroid did not include the same spindle control feature in Acorn similar to All in One DC and likely OAK, that allows -/+ 0-10VDC control natively. SO, it is doable. I made up the same board and Dan and installed it in the DM3000 lathe we were working on, and now in my possession, we tested it with a KB Controller and it worked just like the Dyna DM4400.

I'd love to swap the DM4400 over to Acorn, but alas, when you have a tool changer you need more than 8 inputs and outputs...

SO, its doable, don't fret, we can make it work. My buddy Bill VanOrden has the equipment to etch PC boards, but its a slowish process. If I could have boards etched and drilled then they could be made available....

I would suggest those of you needing the +/- 0-10VDC, continue on and get your machines running in forward so you can make chips. The board could be refitted to the machine.

THOSE USING KB ELECTRONICS DC CONTROLS, YOU MUST USE THE SIGNAL ISOLATOR! ELSE THINGS CAN GET UGLY WITH THE DRIVE (read sparkage and magic smoke gets out!)

[frijoli]

Yes, it has to be plus or minus 10vdc. Not the same as changing polarity.

Now that there is something I don't understand. I have an AMC servo drive I plan to install on my spindle some day and it's controlled by your magic +/- 10vdc. So you guys are saying I won't be able to control it with the analog 0-10vdc signal running through a simple DPDT polarity reversing relay circuit? 'Splain it to me Lucy.

If the drive doesn't have a reversing connection, and only uses "minus" 10vdc to reverse then you will need the board Marty is talking about in his reply. It's not really magic as industrial DC drives have been using this for many years.
The voltage looks like this: +10____0____-10. The 0 zero in the middle connects to common, and the + and - voltage come from the other wire.
What irritates me a little is that I specifically called KB and asked the question and was told all I needed was to reverse the polarity. Fortunately I didn't have too much money in this drive anyway; I did buy a DC motor off eBay. It was cheap too.
I may make the voltage scaler/divider for now, but I am talking to a manufacturer about modification to their drive that would only be firmware change and it will open a whole new option for spindle control.

[frijoli]

Like I also said, SADLY, Centroid did not include the same spindle control feature in Acorn similar to All in One DC and likely OAK, that allows -/+ 0-10VDC control natively. SO, it is doable. I made up the same board and Dan and installed it in the DM3000 lathe we were working on, and now in my possession, we tested it with a KB Controller and it worked just like the Dyna DM4400.

I'd love to swap the DM4400 over to Acorn, but alas, when you have a tool changer you need more than 8 inputs and outputs...

THOSE USING KB ELECTRONICS DC CONTROLS, YOU MUST USE THE SIGNAL ISOLATOR! ELSE THINGS CAN GET UGLY WITH THE DRIVE (read sparkage and magic smoke gets out!)

I wish they had incorporated the +/- 10VDC as well. This would have allowed a LOT more options for motor controls as this is pretty common n industrial applications.

Clay

[ScotY]

Hi Marty,
I've never done it but you can get PCB boards made for really cheap (like almost dirt cheap) but the hang up is you need a cad file of it to send off.