Inverter control

[RobCee]

Has anyone used the GRBL output to control an inverter yet?

I have been playing with my inverter and found that I can start/stop fwd/rev it with a set of NO/NC connections over it's 'Multi-Input' controls if I program it right.

I am looking to hack the inverter control into the GRBL outputs from the Arduino, but am not sure if I should put some sort of optical isolation between them. As it's a Chinese inverter, I'm guessing that I probably should, but am not entirely sure what to use if that's the case.

[zorlack]

Have you had any luck with this?

I'm trying to set up my Hitachi L100 inverter to take instructions from GRBL. Supposedly D_12 should indicate Spindle Enable... but I haven't been able to control it. Its just stuck on.

-Z

[RobCee]

Z - I have had the inverter running using external controls, but am yet to connect it to the GRBL outputs, although I did opt for opto-isolated relays, as I think that is good practise.
I should get it all up and running over the next week or so and will let you know.
It should be pretty simple to check the spindle control outputs from GRBL, with a voltmeter to measure the outputs from Pin D12/D13.

With my Huanyang Inverter I had to program two different areas of the controller, other brands may vary the actual values, but should have similar concepts.
Firstly, you have to tell it to accept external commands over the 'Multi-Inputs':

• Set PD001 to 01 - external terminals as the Source of Run Commands

Secondly, you have to tell it what commands are going to be coming to which terminals in it's 'Multi-Input' section:

• Set PD044 to 01 - for RUN function

• Set PD045 to 05 - for switching of Fwd/Rev direction

This now gives you the ability to have normally open (NO) switches across the terminals marked FOR/DCM and REV/DCM. (Again, different brands may vary the actual terminals, but the concept is common to most inverters)
This is where the physical FOR terminal matches the PD044 setup, physical REV terminal matches the PD045 setup. The DCM is a common connection for the Multi-Inputs.

A similar concept applies to using an external potentiometer to control the speed frequency, setting PD001 to enable external control, then connecting a 10k pot across VR, VI, ACM.

I will be doing both of these for my setup and will post up some images and such once I have it running in situ. I have had both working using breadboards on the desk, just need to build it properly in the workshop now!

/R

[Nigel K Tolley]

What do you mean by an inverter? A box that boosts 12V to 240V, a NOT gate of some form, or something else entirely?


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[RobCee]

Nigel, I mean a device which takes a 240VAC (single phase) supply and converts it into a three phase supply, typically 220VAC or 415VAC, by simulating the other phases in the supply.
This can then be used to drive an AC spindle at a range of speeds by varying the frequency of the output, mine varies between 100 and 400Hz giving me about 8000-24000 rpm at the spindle.

It is this sort of thing: eBay 800W AC Spindle

I prefer to use an AC spindle rather than DC, as I already have a number of 3 phase devices hanging around my workshop and am comfortable with the technology. I probably should think about using DC one day, but I am not sure about all the other elements of the DC circuits; speed control, etc.

[zorlack]

I got everything working last night. I was banging my head against it for hours until I realized that the silkscreen on grblshield is shifted a little and what I thought was D_12 was actually D_11.

The L100 seems to expect 24 volts signaling for its control functions (honestly I didn't even try 5V), but I was able to bypass the problem by using the analog (pwm) input. I connected the +5V line to the +10V analog input, then I was able to configure the L100 to only accept values between +0.5V and +5.0V. So now whenever grbl ends up supporting PWM spindle control, I'll be ready for it!

As for choice of inverter, I'm a big fan of the L100. It does two things well:
1) It lets me run my 800W 3Phase 220 Spindle of a 110V wall outlet
2) Its made by Hitachi, so the documentation if thorough

[Nigel K Tolley]

Nigel, I mean a device which takes a 240VAC (single phase) supply and converts it into a three phase supply, typically 220VAC or 415VAC, by simulating the other phases in the supply.
This can then be used to drive an AC spindle.

Three phase inverter. Got you. Wasn't expecting that - the Shapeoko doesn't seem like it could handle the typically fractional horsepower or higher motors that run on 3 phase.

If you know three phase though, it does make life a lot easier! None of this PWM DC nonsense.

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