help?

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18 Nov 2010 00:24 #5385 by lendrum
help? was created by lendrum
I am setting up a cnc router using, emc2 2.3.0, mesa 7I43 through a parallel port, a pair of mesa 7I40.
When I turn the shafts by hand emc2 shows the table moving but when I ask emc to move the table nothing happens except follow errors. Does anyone have any suggestions?

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18 Nov 2010 01:34 #5387 by cmorley
Replied by cmorley on topic Re:help?
we need way more info to help.
Are you using servos or steppers?
how did did you build the config with pncconf or by hand?
a copy of the INI and HAl file would be helpful.
If its servos off the top of my head is if the encoder and motor don't agree which way are going.
so then the encoder say its going say negative direction but the motor is turning it in positive.
It will follow error real quick.
Does the motor try to move at all?
If the mortor doesn't move at all it will follow error quick too.
how small is your following error set at? tempararaly open up the limits to see if it is a tuning propblem.
send us more info.
Chris m

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18 Nov 2010 02:28 #5388 by lendrum
Replied by lendrum on topic Re:help?
I used the config files that came with emc for the mesa boards.
It is a dc servo system with quadrature encoders.
When the motion command starts, I watch the voltage on the motors and there is no voltage. I reduced the speed to .02 inches/min so it takes time for the follow error to happen but the motor never gets any voltage.

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18 Nov 2010 03:55 - 18 Nov 2010 04:05 #5389 by PCW
Replied by PCW on topic Re:help?
The 7I40 needs 4 main things to drive the motor:

1. Motor power (on the bottom terminal block)
2. Adequate 5V power (is the gate power yellow LED CR1 (upper left of card) on?)
3. PWM signals (must be high for drive, EMC should have this set up)
4. /ENA signals (must be low to enable a channel, EMC should also have this set up)

The two Yellow LEDs, CR8 (chan 1) and CR9 (chan 0) should illuminate if you have PWM and /ENA
Neither red LED should be illuminated
Last edit: 18 Nov 2010 04:05 by PCW. Reason: chans swapped

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18 Nov 2010 12:41 #5399 by andypugh
Replied by andypugh on topic Re:help?
lendrum wrote:

follow error to happen but the motor never gets any voltage.


Sounds like an amp-enable problem. (or zero Gains in the PID)

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19 Nov 2010 07:52 #5427 by lendrum
Replied by lendrum on topic Re:help?
The 5 volt supply to the boards was weak. With the just the boards it was pulled down to 4 volts and when I added the encoders it dropped to 3.5 volts which was not enough to drive the gates. Now I move onto tuning.

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