PM940CNC

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ralyks91
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24 Jul 2021 00:10 #215722 by ralyks91

PM940CNC was created by ralyks91

Bought a PM940 CNC a couple years and have been slowly getting it working. Didn't bother with mach3 and went straight to linux cnc. I've made a good bit of progress from reading others who have converted there 940 over to linux and following tutorials on this forum but running into some issues as I'm really new to linux and with all the wires in the machine

. Been a machinist for over 10 years just never messed with the insides of the machines. Probably bit off more then I can chew but I'm patient and willing to learn just need some help. so far i have linux installed on and old dell xps 420 and have it connected to a mesa 7i76e board. I've got the pc and board talking together, currently working on getting the spindle to function. The vfd is a delta(model:VFD015E21A) i found the basic configurations on the forum but still not sure what to do lol. I believe it needs to be setup as an analog signal. Have been using this guys stuff as reference and a rough guide: My PM-940 CNC Modifications | Page 3 | The Hobby-Machinist
Any help would be fantastic thanks

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andypugh
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24 Jul 2021 10:11 #215757 by andypugh

Replied by andypugh on topic PM940CNC

Have you gone through the parameters in the drive to check what the current settings are?

Note that you won't be able to change anything unless 00.02 = 0

Assuming that the VFD is already set up for the spindle (?) then it looks like you just need to set 02.00 = 1 to enable 0-10V control.

You shuld test the voltage between 7i76 pins TB4-1 and TB4-3 (should be 10V, from the VVD) and then check that changing the spindle speed in LinuxCNC causes the voltage between pin TB4-1 and TB4-2 to change.
If it doesn't then the problem is in the LinuxCNC config.

The forum thread that you linked to has two relays to control the VFD. These appear to be used to convert VFD FWD/REV control to the RUN/DIR control that the 7i76 outputs. This appears not to be necessary, as the VFD can be configured for RUN/DIR by setting 04.04 = 1.

The VFD has an internal switch to choose between NPN mode and PNP mode. The 7i76 ENA and DIR outputs behave as switches (though with a specific polarity which must be considered). I think that I would configure in NPN mode (ie, connect a terminal to DCM to enable it) so that the 7i76 ENA- (TB4-5) and DIR- (TB4-7) connect to the VFD DCM and then ENA+ (TB4-6) connects to VFD MI1 and DIR+ (TB4-8) connects to VFD MI2.

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ralyks91
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31 Jul 2021 20:59 #216495 by ralyks91

Replied by ralyks91 on topic PM940CNC

thanks for the reply, working through what you said and have a question. On the TB4 pins should I only have those pins connected you mentioned(5,6,7,8) or do any others need to be connected also?

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andypugh
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31 Jul 2021 21:15 #216499 by andypugh

Replied by andypugh on topic PM940CNC

You need to connect the +10V 0V and analogue voltage pins too, I think.

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ralyks91
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31 Jul 2021 21:47 - 31 Jul 2021 23:15 #216507 by ralyks91

Replied by ralyks91 on topic PM940CNC

found this, guessing your referencing to this post?

www.forum.linuxcnc.org/49-basic-configur...7i76e-to-delta-vfd-e

Update: Made a little progress today, watched some videos on the vfd and was able to change it to use the digital key pad and potentiometer. spindle works!! now just to connect it to the mesa board.

Last edit: 31 Jul 2021 23:15 by ralyks91.

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