Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: dmoore on March 28, 2009, 08:52:49 PM
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After spending dozens of hours writing code and troubleshooting a Mach3 to VFD control interface, I wondered if there was interest out there in having someone create a simple plug-in VFD interface (not using brains and vbscript). It appears that the majority of people today control their VFD's with simple NO contacts without the benefit of VFD spindle speed control, VFD error reporting and VFD current draw feedback. It occurred to me that there may be a market for someone to build VFD specific plug-in's for Mach3 that provide all those functions right out of the box.
This is assuming that the VFD supports Modbus or serial communications.
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Pretty much everyone I know with a VFD *is* using Mach to control spindle speed, through a DigiSpeed or similar interface. I don't know anyone doing any error capture, but then the low-end VFDs (I have a TECO FM-50) I don't think provide that.
Regards,
Ray L.
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Pretty much everyone I know with a VFD *is* using Mach to control spindle speed, through a DigiSpeed or similar interface. I don't know anyone doing any error capture, but then the low-end VFDs (I have a TECO FM-50) I don't think provide that.
I agree that there is additional cost in a VFD that supports RS485/RS232 (Teco SV-7300 @ $320) over one that doesn't (Teco FM-50 @ $120) which is neccessary for true two-way control/feedback. With the additional cost of adding in a Digispeed/PMDX-106/etc, the additional cost of a VFD with RS485 comes more into line with an analog solution.
I'm curious - to you, which is more important - overall cost (excluding your time input) or functionality?
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I'm curious - to you, which is more important - overall cost (excluding your time input) or functionality?
Well, since I've never had a problem with my VFD, I'd have a hard time putting error handling very high on my list. If the VFD faults, I'll probably know why. I suspect it depends a lot on the kind of machine you're running. Mine is a CNC'd BP clone, so when something goes wrong, I know immediately what caused it, since I'm right there. And the spindle is about the most reliable part of the whole machine, and the strongest. On a larger machine, like a VMC, I could see something like that being more useful.
Regards,
Ray L.
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I don't really see the need for a plugin as control via Mosdbus can be done with a few lines in a macropump or a simple brain
Cheers,
Peter.
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I'd likely buy a serial VFD control plug-in if it didn't break the bank too badly, currently I'm controlling my VFD via a analog output from my breakout board, but the accuracy is around +/- 5%, which causes me some problems when tapping.
Paul T.
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As stated above, get something like a Hitachi VFD that supports Modbus right out of the box. You remove the control panel and there is an RJ45 modular jack behind it. Get a USB to RS422 converter and make a 3 wire cable adapter that goes from the RS422 to the modular connector. I cut the end off a phone cord and soldered a DB9 on the end.
Then write a few lines of scripts and it will work. I could even post my code but I think some other already have.
No cost at all except for the RS422 to usb.
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Boilerbots, could you please post that VFD code so I can see what I'd be getting into if I decide to try to set this up?
Thanks,
Paul T.
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Absolutely! I have a Delta VFDs and I would love to know motor draw/load and RPM drop to help make better cuts. Like most most I rely on specific experience with materials and tools and also the sounds the tool is making during a cut... this is good, but measured info would really tell me if I can afford to spped things up.
btw - spindles are Perske 3hp @ 24k rpm and Colombo (w/ATC) 10hp @ 24k rpm.