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Author Topic: Machine wont zero after Homing  (Read 19637 times)

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Re: Machine wont zero after Homing
« Reply #40 on: April 23, 2014, 10:37:39 AM »
there are 2 points just under the pot on the board

Offline stirling

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Re: Machine wont zero after Homing
« Reply #41 on: April 23, 2014, 11:30:39 AM »
Power supply is 24V / 20A.
Gantry is waiting A Axis driver. Only have 3 at the moment. 4th in transit.
Will Check the voltage using the forumla you supplied and see if its somewhere near. Where do i put my meter to measure the Vref ?

Hmmmmm. Your power supply is not ideal - problem is you're already running your motors at little more than half their potential. Not enough V, but more Amps than you could shake a stick at.

It's not MY formula - don't be blaming me when it all lights up ;D - it's right there on YOUR board. If not then the piccy you linked to is different. Check the manual.

there are 2 points just under the pot on the board

Hmmmmmm. are you sure they're the points you need to be measuring? Again from the piccy - there's two terminals on top of the board marked VRef and Gnd. You may be right - they may be the same thing - You guys have the boards and manual. Just checking.
Re: Machine wont zero after Homing
« Reply #42 on: April 24, 2014, 04:18:21 PM »
Ok - If all else fails RTFM!

Your both absolutely right. The formula you gave is on the manual. (1 piece of paper.)
I have now accurately set the Ampage fairly accurately to 3Amps on all pots. (Which seems to equal 1.36 V) across the two terminals.

e.g. (1.36 * 0.333) / 0.151 = 2.999A

As I think i mentioned my programs have been crashing 1/2 way through. I initially thought this was interference, but tonight i have successfully run
programs in mid air with the cutter running, and then cutting mdf on a very slow feedrate.

I suspect the crashes occur when the motors are under more load. E.g. When the feedrate or cut depth is higher.
I did have a feedrate of 1500, and now i have dropped it to 1000.

Looking at the manual, the drivers say they have TSD (Thermal shutdown), Over Current Detection (ISD) and built in Under Voltage Detection (UVLO).
I suspect that one of these is kicking in at higher feed rates. I expect Over Current Detection - the boards are not getting hot.

Do you think a higher voltage power supply would solve this ?
What would you recommend in terms of volts required - Just reread your post.

Where the hell am i going to get a 36V 12A power supply from?

Thanks for your very useful help...

Martin
« Last Edit: April 24, 2014, 04:29:47 PM by mturneruk »
Re: Machine wont zero after Homing
« Reply #44 on: April 25, 2014, 04:39:33 PM »
OK - So I now have screened cables all-round and I am still get skips, blips and judders at random points when jogging.
Sometimes it doesen't do it immediately, but then soon starts. Sometimes its really bad. I can't find a pattern...

When i am running a program, it seems fine.
I have ordered a 36V power supply, so hopefully that will hope with the program stopping 1/2 way through

Offline Tweakie.CNC

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Re: Machine wont zero after Homing
« Reply #45 on: April 26, 2014, 02:11:40 AM »
My post has been deleted as it fell on deaf ears  :-[

Tweakie.
« Last Edit: April 27, 2014, 07:58:43 AM by Tweakie.CNC »
KEEP SAFE !