Messages

1

Mach4 General Discussion / Re: Help with maths on variables in PMC - Feedback from VFD

« on: January 15, 2021, 02:14:47 AM »

Thanks compewter_numerical!
That makes sense - the variable needs to be initialized with a value before it can be worked with.
There is no way i would have worked out that flow myself. Much appreciated. 

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Mach4 General Discussion / Re: Help with maths on variables in PMC - Feedback from VFD

« on: January 12, 2021, 02:47:53 PM »

Not sure how Mach handles values from Modbus. Could be treating it as a string which would explain the issue.
Will keep tinkering and see if I can nut it out.

Thanks again for taking the time to assist Bob.

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Mach4 General Discussion / Re: Help with maths on variables in PMC - Feedback from VFD

« on: January 11, 2021, 05:47:37 PM »

Thanks Bob. Appreciate you spending to the time to look at my issue, but unfortunately no go.
If you hit simulation mode, it gives the variable unassigned error pops up for variable VFDHz.

Tried generating LUA code and assigned a readout on the screen to display RPM in case the reported error was incorrect, but just get zero when the spindle is running and the Modbus register is showing the correct value.

If I assign the Modbus register to display on the screen, it works without a hitch. Just can't seem to assign a math operation to the variable. 

4

Mach4 General Discussion / Re: Help with maths on variables in PMC - Feedback from VFD

« on: January 11, 2021, 02:50:00 PM »

PMC File attached.

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Mach4 General Discussion / Re: Help with maths on variables in PMC - Feedback from VFD

« on: January 11, 2021, 02:35:25 PM »

Thanks Bob - Just realized that the first image I uploaded must have got cropped. The SpinRPM variable is the set speed from Mach4 that I am dividing by 6 to get the Hertz required and sending to my VFD with the RPMset variable.

What I need to do now is read back the real time VFD output so I can display the speed on screen.

I can read the VFD Hertz output register via Modbus no problem and using PMC, I can move the VFD Hertz output into a variable which I have named VFDHz, but I cannot multiply that value to get an indication of the spindle RPM.

6

Mach4 General Discussion / Re: Fanuc 6 Axis Robot Arm Help with Concept

« on: January 11, 2021, 03:38:16 AM »

That was my first thought; 'why would you want a robotic arm?'. Then the 350 dollar price tag changed that thought into why wouldn't you want a robotic arm.

The what to do with it question can come later.

But they are obviously mainly used for repetitive work (hence the bartender suggestion) so I will be interested in seeing what other people come up with.

7

Mach4 General Discussion / Re: Fanuc 6 Axis Robot Arm Help with Concept

« on: January 11, 2021, 03:21:30 AM »

$350 for that beast?!?! It has almost a 3 meter horizontal reach!

Please tell me you plan to mount on the bench between the couch and the fridge and have it hand you beers at the push of a button. The ultimate home automation solution. 

8

Mach4 General Discussion / Help with maths on variables in PMC - Feedback from VFD

« on: January 09, 2021, 09:07:47 PM »

I have set up Modbus comms between my Powerflex VFD and Mach4 and I am able to control the spindle, read status logic bits, etc, but I was hoping to get the output frequency from the drive and display it as an RPM DRO on my screen. To control the speed on my spindle via PMC, I am taking the Core Val 'Spindle RPM', putting it into a variable and dividing by 6 to get the required Hertz. Then writing that variable to the VFD register.

When I attempt to do the reverse with the VFD Hertz output register, I can move the register value with a Read Reg instruction and the variable shows the correct value in the bottom section of the PMC editor. But if I try to multiply the value by 6 at the end of the rung, I get the following message
"Variable 'VFDRpm' not assigned to, e.g. MOV statement, and ADD statement, etc. This is probably a programming error; now it will always be zero."