Tb6560 3axis & spindle motor control?
I have a sherline 5410 mill that came with most of a retrofit kit from backtrack mfg. I'm going to be using a tb6560 3axis blue board for stepper drive and I'm hoping I can get spindle control as well. I'll be using mach3 with this setup and I also have the motor control from an old spectralight mill. It's made by minarik drives inc. It's model # PCM21000A. The manual for this drive says it will follow a 0-10vdc output signal to control motor speed. Is it possible to get this type of signal with the tb6560 and mach3 or do I need another source for this signal. I have the manual for the motor drive if that helps. I can possibly upload it if need be.
Kevin.
Nsr customs.
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The blue 3-axis TB6560 boards that I have seen do not support PWM control of spindle speed. Rather, they have a simple on-board relay that may be used to turn the spindle on or off.
To use PWM spindle speed control you would probably have to use a separate board such as the C41 from CNC4PC (CNC4PC), but you would have to find a couple of unused parallel port pins and grab them from the TB6560 board.
Looks like your Minarik is an SCR instead of a PWM controller: "The PCM20000A Series of drives are a cost-effective solution for variable speed, process control applications from 1/20 to 2 HP. These are SCR drives that integrate isolation allowing them to accept external analog process control signals. Alternative solutions require users to wire a separate isolation card to the
drive which adds cost and reduces available space."
As doorknob says you will need a separate 0-10v analog speed control board to get Mach to control the speed. Peter Homann, CNC4PC, Bob Campbell are a few suppliers. Get an opto spindle speed sensor and make a disc to go on your spindle to read out the speed as well. I use a CNC4PC C3 myself.
Sounds like you won't have the misery I had getting my CNC4PC speed control to work with a KB brand SCR controller since it looks like the Minarik has built in isolation. This is a critical issue because if correct isolation isn't obtained, things will go FLASH-POP! on a CNC4PC board the 1st time you ask Mach to turn the spindle on. DAMHIK
I had to get a separate isolation board as mentioned above. Fortunately I was able to fix the vaporized track on the CNC4PC board and it all works well now and a good, used KB signal isolator board was only $30.00 on ebay.
If you're an electonics dunce like me, make sure you bone up on this isolation stuff or ask lots of questions! Mains power is a terrible thing if you get careless.
"Looks like your Minarik is an SCR instead of a PWM controller" - SCR motor speed controllers *ARE* PWM controllers. They simply use SCRs for switching the power instead of FETs.
Told'ja I was an electronics dunce.
But not QUITE the same, PWM typically use a higher frequency than the mains frequency of 120Hz (Rectified 60Hz), PWM is often around 2kHz and higher.Originally Posted by HimyKabibble
SCR Uses phase angle switching of the incoming AC, whereas PWM is a square wave pulse of modulated width from a fixed DC power source.
But I think the initial discussion about PWM was referring to the command signal type not the type of power switching?
Al.
Last edited by Al_The_Man; 12-23-2012 at 04:44 PM.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
Ok so I'm still a little lost. If I'm understanding all the info I've gathered correctly, mach3 will put out a pwm signal on an unused pin in the db25 parallel port to control spindle speed?
If that is correct then I need to purchase a device that will convert a pwm signal to a voltage signal from 0-10vdc?
What is the lowest cost option for that?
Is it going to be cheaper to purchase a new controller that will accept a pwm signal instead?
Will I need an external rpm sensor or encoder to signal back to mach3?
I'm having to go the bear bones cheapest route to get this thing running for now. Seeing as I was just laid off funds are really tight and I am hoping to be able to use this machine for some work I have to complete for my final project in my associates program at ITT tech.
Thanks for the help.
Kevin.
Nsr customs.
Go to: Speed Control (DigiSpeed) : Homann Designs!, The preferred CNC Component Supplier
The DigiSpeeds work great. Much better than the others I've tried. Peter Homann is a regular on here, so you'll get good support as well.
Regards,
Ray L.
Well that seems to solve my issues in one step. He has an almost drop in solution for sherline spindle controls.
Thanks.
Kevin.
Nsr customs.
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