Topics

1

Brains Development / Out-put control word to sequential range of coils (Danfoss VFD)

« on: April 22, 2011, 07:48:53 AM »

HI Guys,
Iv'e watched the tutorials and read the Popper Bears brain guide but I still can't work out how to send to or read from multiple coils (16) in a brain.
It's got to be something easy that I am missing.

My Danfoss VFD has the control bits in coils 0-15 and the spindle speed setting bits in coils 16-31 (speed range 0h - 4000h). Coils 32-47 are the VFD status bits and then coils 48-63 are the spindle speed feed back bits.
Words are sent LSB first

I can control and read from the VFD in the Modbus test screen. The VFD can be stopped by addressing just one bit in the control word but will not start using that method. I have to write to the full 16 coils of the control word.
Each coil only accepts a 0 or 1. 

I imagine the value in the brain would be a decimal representation of the binary word, but I don't know how to break that up for sending to the individual coils in one action.

Any pointers on reading 16 consecutive coils and processing them as a 16bit word, and/or sending a 16bit word to 16 coils?

Cheers,
Phil

Setup Images

2

General Mach Discussion / Possible to keep limits enabled during home?

« on: April 04, 2011, 12:29:26 AM »

Hi Guys and Gals,
I have a 3 axis mill with all limits and home switches wired to separate inputs on my BOB. Yep nine inputs.
I Set up the mill b4 I had Mach running and wired the limits this way because it lets you safely jog off a limit without disabling the limit, and it's normal practice here at work for motion control systems. ( would be great if I could replicate this in Mach as well)

Is it possible to edit the homing routine (DoButton24 etc) to leave the limit inputs enabled during the home all sequence.

My home positions are 20mm inside the closest limit and if I inadvertently home from within that space the limits are of no use at all, the mill will drive to the end stops and stall the steppers.
I understand why Mach is set up this way, I just want to keep the fail safe features that I have implemented enabled during home.

Cheers,
Phil

3

General Mach Discussion / Possible G2, G3 bug

« on: March 05, 2011, 10:29:21 AM »

G'day guys and gals,

I was trying out Cambam plus a couple of nights ago to make a 2.5D bracket for the mill.
After generating the G-code in Cambam I ran it through CutViewer Mill to check it and then as a final check loaded the G-code into Mach3 that I have on the house computer (Version R3.042.022 I think, certainly low 20's).
All looked good.
I then popped out to the shed and loaded it onto the mill computer (Version R3.042.028 from memory. definitely high 20's). It came up with a large circle in one of the outside corners. (image attached)
I ran an air cut thinking it was just an display artifact, but it wasn't. I then upgraded to the current lock down version (Version R3.043.022) and loaded the G-code again. Still had the circle. Finally I upgraded to the latest beta version (Version R3.043.028) and still no change.
I looked at the G-code to try and see the problem and tracked it down to the G3 statement "G3 X159.7813 Y-42.3477 I1.75 J0.0"
The G-code seems correct and this is backed up by a run in CutViewer, but Mach has an issue with that line. I edited the G-code and changed it to a G2 command. That solved the problem in Mach but leaves CutViewer following the correct definition of G2 and taking a bite out of the part.

I don't think it is hardware related, I get the same results in Mach3 both in the house ( Win7 64bit) and shed (XP 32bit).

The pictures and G-code with the suffix "raw" are as outputed by CamBam with tool and stock defined in CutViewer.
The pictures and G-code with the suffix "edited" are the ones I changed to G2.
Black circle in CutViewer images indicates the problem corner.
Mach images has the offending code line highlighted

Has anyone come up against this problem B4?

Cheers,
Phil