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Author Topic: Display of analogue input?  (Read 3829 times)

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Offline Davek0974

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Re: Display of analogue input?
« Reply #10 on: October 17, 2016, 06:44:53 AM »
Nice

ta
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives.
Plasma table, Mach3 V062, Step motors, C&CNC THC.

Offline Davek0974

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Re: Display of analogue input?
« Reply #11 on: October 17, 2016, 01:28:42 PM »
Well, that was too easy, almost a non-event :)

Programmed the vfd, hooked up the analogue output to the CSMIO, added the line to the macro-pump and updated the screen-set.

https://youtu.be/K8mDCgCgBZU

Not sure on scaling yet, if 2200W is 100%, what % is 400W??
« Last Edit: October 17, 2016, 01:31:42 PM by Davek0974 »
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives.
Plasma table, Mach3 V062, Step motors, C&CNC THC.

Offline Hood

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Re: Display of analogue input?
« Reply #12 on: October 17, 2016, 01:43:21 PM »
100/2200 x 400 = 18.1818181818%

Offline Davek0974

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Re: Display of analogue input?
« Reply #13 on: October 17, 2016, 02:01:19 PM »
Nice, thanks.

will tweak the scaling factor in the vfd a little :)
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives.
Plasma table, Mach3 V062, Step motors, C&CNC THC.

Offline Davek0974

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Re: Display of analogue input?
« Reply #14 on: October 17, 2016, 03:06:59 PM »
Seems like it may be a typing error that caused the disparity in readings - the quick start manual i got the 150% output from does not match the full manual i just downloaded which states 120% output power.

Using 120% as max now gives me a divisor of 34.125 of the DAC input and a quick trial and error calculation gives me a display of 17.9% or thereabouts - almost spot-on :)

Will change the macro tomorrow.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives.
Plasma table, Mach3 V062, Step motors, C&CNC THC.

Offline Hood

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Re: Display of analogue input?
« Reply #15 on: October 17, 2016, 05:13:36 PM »
Is that really the spindle load?
Usually it is the current that is looked at to determine the load but  that is with servos, it may be  the VFD itself is using the current and converting to Watts for the display?

For my load meter I used the continuous rated current for 100% and have it scaled so that 10v is equal to 150% of rated current. Unfortunately my servo drive will put out +/- 10v depending on the direction so I couldn't use the analogue input of the PLC to take it to Mach. I made up a wee board that would invert the voltage if a negative but failed miserably trying to make an amplifier to account for the losses in the rectifier diodes. Ended up just hooking up an analogue meter and it works well.
https://www.youtube.com/watch?v=lZ7asQ2PBGQ

Hood

Offline Davek0974

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Re: Display of analogue input?
« Reply #16 on: October 18, 2016, 02:20:49 AM »
This sounds familiar, Hp, kW, Torque..... ;)

I have no idea really, I just presumed that if the motor is rated 2.2kW and the output is showing 0-10v as 0-120% of 2.2kW then that must be the figure to use, I can switch the output to 0-120% of rated motor Amps instead if that is better?

Is that not the same as reading motor watts? Surely if the motor is flat-out then it makes no odds what you read as they will all be 100% motor rated values?

Is there a difference?

What is spindle load measured in ? Nm, kW, motor Amps??

Seems i have all values to play with so whats best ?
« Last Edit: October 18, 2016, 02:24:12 AM by Davek0974 »
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives.
Plasma table, Mach3 V062, Step motors, C&CNC THC.

Offline Hood

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Re: Display of analogue input?
« Reply #17 on: October 18, 2016, 02:47:57 AM »
The units of a load meter? Load I suppose :D
As I said usually it would be current, the harder the spindle has to work then the more current it requires. Now whether your VFD is doing that in the background and giving you a KW display I have no idea.
Might be possible to test, if you can put a load on the spindle and see if the KW ramps up, maybe put a holder with a length of steel in it. Have it close to a vice and then start the spindle (slowish) and use a brush shaft to lever between the vice and the steel in the holder and see if the KW ramps up as the load increases.

Hood

Offline Davek0974

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Re: Display of analogue input?
« Reply #18 on: October 18, 2016, 02:56:57 AM »
Oh, it certainly ramps up :)

I just have to flick the spindle brake to get it to peak :)

The BP brake is what, about 5" dia by 5/8" tall? So that represents a massive load compared to a small cutter, you only have to bring it on lightly when running to get a full-power load for a second or two;)
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives.
Plasma table, Mach3 V062, Step motors, C&CNC THC.

Offline Hood

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Re: Display of analogue input?
« Reply #19 on: October 18, 2016, 02:59:44 AM »
That sounds fine then, looks like the KW display is indeed being linked to the load on the motor and is not just related to rpm. :)

Hood