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Author Topic: I messed up with my new bench: EMF  (Read 6388 times)

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Re: I messed up with my new bench: EMF
« Reply #10 on: January 26, 2016, 06:37:46 PM »
You should try another PC, this one seems to have bad latency issue or use some motion controller for generating pulses if you need more than 25khz for step lines.

Offline Mogal

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Re: I messed up with my new bench: EMF
« Reply #11 on: February 14, 2016, 09:55:49 PM »
I have my steppers set at a speed of 140ipm.
The DRO reads out 152ipm when I rapid move.
Any ideas to this one?
Got me completely stumped :(
Re: I messed up with my new bench: EMF
« Reply #12 on: February 15, 2016, 07:31:52 AM »
Two things, if the rapid is two axis moving at the same time then the combined velocity will be higher than either axis alone. Its a rapid, be happy that it goes as fast as possible when not doing any cutting. As long as position is correct you are good to go.

Offline stirling

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Re: I messed up with my new bench: EMF
« Reply #13 on: February 15, 2016, 08:47:27 AM »
BUT!

I have my steppers set at a speed of 140ipm.
The DRO reads out 152ipm when I rapid move.

Turns out the frequency is actually 27,300 pulses (Not 25,000)

There's your answer right there in the numbers.

27300 / 25000 = 1.092

1.092 * 140 = 152.88

Unless your PC shows a rock steady exact 25000 pulse frequency (which I'd be surprised if anyone's does) then this is what happens.

Perhaps more curiously, when I FIRST start Mach, the actual pulse frequency is a rock steady 25,324. However if I close and restart, this drops to a rock steady 24,397. If I close and restart again it's rock steady at 23,674. Closing/re-starting from then on has no further effect and it remains at 23,674. If I re-boot then the whole (3) cycle will repeat exactly. Just one of those Mach3 things I suppose.

Offline Tweakie.CNC

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Re: I messed up with my new bench: EMF
« Reply #14 on: February 15, 2016, 08:53:15 AM »
Quote
Perhaps more curiously, when I FIRST start Mach, the actual pulse frequency is a rock steady 25,324. However if I close and restart, this drops to a rock steady 24,397. If I close and restart again it's rock steady at 23,674. Closing/re-starting from then on has no further effect and it remains at 23,674. If I re-boot then the whole (3) cycle will repeat exactly. Just one of those Mach3 things I suppose.

How on earth you discovered that beats me - it appears that the more I learn, the less I know about Mach3.  :'(

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.

Offline stirling

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Re: I messed up with my new bench: EMF
« Reply #15 on: February 15, 2016, 11:15:29 AM »
I'd be very happy to tell you exactly how I discovered it - if only I could remember  ;D

Offline Mogal

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Re: I messed up with my new bench: EMF
« Reply #16 on: February 15, 2016, 03:17:18 PM »
BUT!

I have my steppers set at a speed of 140ipm.
The DRO reads out 152ipm when I rapid move.

Turns out the frequency is actually 27,300 pulses (Not 25,000)

There's your answer right there in the numbers.

27300 / 25000 = 1.092

1.092 * 140 = 152.88

Unless your PC shows a rock steady exact 25000 pulse frequency (which I'd be surprised if anyone's does) then this is what happens.

Perhaps more curiously, when I FIRST start Mach, the actual pulse frequency is a rock steady 25,324. However if I close and restart, this drops to a rock steady 24,397. If I close and restart again it's rock steady at 23,674. Closing/re-starting from then on has no further effect and it remains at 23,674. If I re-boot then the whole (3) cycle will repeat exactly. Just one of those Mach3 things I suppose.

Okay, thanks for verifying that for me...
Know that I "know" its okay I can continue with the next step.

So...

@ 25k pulse, everything 'seems' to be good, but at 35k pulse, I'm losing steps...