Looking for help with a Mitsubishi Inverter

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Clutch57
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Looking for help with a Mitsubishi Inverter

Post by Clutch57 »

Our current problem is; we just installed a new All in One (AIO) system where as the old AIO (20+ years) system stopped working. All the old components were in this machine when we got it and nearly like new (this not a production machine and has only one occasional job).

The whole machine seems to be fine after the upgrade except for the Spindle’s speed, this unit does not have an encoder on the spindle motor.

If I input 50% into the Centroid panel the VFD will run very high speed (sounds like a jet taking off and is showing 76 Hz on the Mitsubishi’s display and has 9 VDC going into the inverter from the AIO. The settings in the inverter are supposed to go to 120 Hz max, so this is not scaling correctly.

At 50% we should have 5 VDC and 60 Hz approximately on the display as far as I can tell, and I do not dare take it to 100% as something would smoke. Is there a solution to this dilemma?

None of the set points in the Inverter were changed in this process and it worked on the previous AIO before it went out.
Attachments
Mitsubishi.zip
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cncsnw
Posts: 3763
Joined: Wed Mar 24, 2010 5:48 pm

Re: Looking for help with a Mitsubishi Inverter

Post by cncsnw »

Check your high/low range switch input.

If you need help with that, post a Report from your control.

Are you sure your VFD isn't programmed for a maximum output frequency of 90Hz?
cncsnw
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Re: Looking for help with a Mitsubishi Inverter

Post by cncsnw »

A typical CNC11/CNC12 PLC program expects the high/low range switch to be open in high range, and closed in low range.

That is opposite the usual practice on CNC7/CNC10 systems.

Since you apparently upgraded a CNC7 system, you will either need to rewire the range switch (e.g. to use N.O. contacts instead of N.C. contacts); or reposition the switch (to trip in high range instead of in low range); or invert the range input (probably INP13, but you need to look at your PLC program to be certain).
Clutch57
Posts: 8
Joined: Wed Jul 14, 2021 6:03 pm
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Re: Looking for help with a Mitsubishi Inverter

Post by Clutch57 »

So as best as I can see the input is inp13 and it is a NO switch, but when it is in low gear it is closed, which is where it has been for years. if I swing the lever over to the other end the spindle does go slower, but that end of the lever is labeled OUT (not sure what that means so we never touch it).

What report do I run? When I run "Test" I get a 511 missing parameter, line 1020"

The VFD is set at 120 Hz max
Clutch57
Posts: 8
Joined: Wed Jul 14, 2021 6:03 pm
Acorn CNC Controller: No
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DC3IOB: No
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CNC11: No
CPU10 or CPU7: No

Re: Looking for help with a Mitsubishi Inverter

Post by Clutch57 »

I think this is the report you want to see.
Attachments
report_0008DC111213-1015202487_2021-07-15_12-41-53.zip
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cncsnw
Posts: 3763
Joined: Wed Mar 24, 2010 5:48 pm

Re: Looking for help with a Mitsubishi Inverter

Post by cncsnw »

1) Press Alt-i for the PLC Diagnostic display
2) Press the right arrow key 12 times, to move the highlight box to INP13
3) Press Ctrl-Alt-i to invert the highlighted input
4) Verify that INP13 now shows Red in high range and Green in low range

Post a picture of the back gear lever, switch, and placard that says "OUT". Don't pack the picture in a ZIP file; just attach the .jpg file to your post.
ashesman
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Re: Looking for help with a Mitsubishi Inverter

Post by ashesman »

Are you sure the VFD is configured correctly? Maybe the old controller didn't have 5V = 60 Hz scaling? If you do not want the motor to run high frequency then you should limit that in the VFD. Also, that would get you better precision from the Centroid. So set the VFD to 10V = 60 Hz. That way it will never go over 60 and you are using 100% of your analog voltage range. That would halve the scaling and drift errors that are present on the analog output.

The scaling of the analog out is determined by SV_PC_CONFIG_MAX_SPINDLE_SPEED in the PLC program. I believe this is set by the maximum spindle speed settings in the main machine setup screen. But, that does depend on the high/low range so you will need to do that diagnostic first as previously instructed.

You could try setting both high/low max speeds to the same value to take high/low out of the equation.
Clutch57
Posts: 8
Joined: Wed Jul 14, 2021 6:03 pm
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DC3IOB: No
CNC12: Yes
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CPU10 or CPU7: No

Re: Looking for help with a Mitsubishi Inverter

Post by Clutch57 »

Here is the picture, I could also just rewire the switch if needed.
Attachments
PXL_20210716_134332054.NIGHT.jpg
Clutch57
Posts: 8
Joined: Wed Jul 14, 2021 6:03 pm
Acorn CNC Controller: No
Allin1DC CNC Controller: Yes
Oak CNC controller: No
CNC Control System Serial Number: none
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No

Re: Looking for help with a Mitsubishi Inverter

Post by Clutch57 »

@ashesman
I dropped the Hz down to what you said in the VFD, it now runs slower. However the PLC is still capable of running the voltage over 10 VDC, so at 50% we are already at 8.5 VDC from the PLC. The VFD is still responding to the voltage being fed from the PLC. I would like to limit what the PLC is outputting and then I can tach it and tune it.
cncsnw
Posts: 3763
Joined: Wed Mar 24, 2010 5:48 pm

Re: Looking for help with a Mitsubishi Inverter

Post by cncsnw »

When you say "at 50%", do you mean according to "spindlebenchtest.cnc"?

Or do you mean that you selected Manual spindle mode, pressed the "100%" button to set the speed to half of maximum, and pressed Spindle Start?

My guess is that you are running "spindlebenchtest.cnc", but that you neglected to set the maximum spindle speed for high range, on the Control Configuration screen, to 3000 RPM.

In your current control configuration, you have the maximum spindle speed in high range set to 1720 RPM. Therefore if spindlebenchtest.cnc commands 1500 RPM and tells you it is "50%", it is really 1500/1720 = 87.2%.
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