PWM Logic High pin 4 not working on Laser output

[baccus61]

Here are some pictures of my setup and the DSP board.

The wiring is really crappy but I have rewired it probably 15 times so I am not bothered with making it tidy at the moment.
When I need to do Raster engraving I have to revert to the old Linkmotion set up which means I rewire the whole thing which takes about 10 minutes to do. (I can do it blindfolded now) Then I just re-enable the old software.
I replaced the X axis drive pulleys and belts with XL type and not the XML which was way too small in the tooth.
I still have the same problem. I just can't get below 1mm offset when engraving.
I tried pins 1-4 again for the umpteenth time and all I get is 4.8 volts constantly with no modulation.
I tried Laser with NO pre-ignition. Still the same
The X axis limit switches don't work. The light on the board lights up but the board wont recognize it so it keeps banging it's self to pieces when homing.
I wish I could turn the Auto home function OFF. It wastes too much time and is a pain when it doesn't work properly.

[baccus61]

Here is a video of what is happening. It didn't turn out very good so if you can't see what's going on then I might have to make another one. Some of the video of the monitor is very hard to see. The Youtube encoding has distorted it a fair bit you you can still see what is happening.

http://www.youtube.com/watch?v=CzoBP01AbuA

I haven't got the X-axis limit switch working either. That's another problem. The led on the board works but the board won't process the switching and stop or reset the home limit.

Rich.

[Tech_Marco]

The X limit connection is 1 and 4 while Y limite is 1 and 2

If you can't get it work, you can send it back for exchange. I have 3 unit arrived

[Tech_Marco]

One more thing you need to pay attention. The polarity of X & Y limit is selectable from the software. You need to double check it. See page 6/12 of the "Specification of MC-Board.pdf"

[baccus61]

Thanks Marco for your patience through this. I would love to just get it working and be able to do things like everyone else. My hopes are that I can in the near future. It get's so frustrating sitting at the table day after day with the same negative results.
The best thing about the boards are that they are very configurable, but it is also the worst thing as there are so many variables to take into consideration to get it all set up.
Thanks,
Richard.

[Tech_Marco]

This is a tech support forum. For return or other sales issue, please contact me by email.

Marco

[baccus61]

I swapped the RH X limit wire from 5 to 4 and swapped all the setting about in the software and now it's working fine. Thanks for that.
I also tried the laser settings on pin 5 but I still get the same result. No lasing on 5, full power all the time on 4 and modulation on 3 but with double image 1mm apart.
Rich.

[Tech_Marco]

Manually set the power to 50% and the output should be 2.4~2.5V
If no, then you need to send it back for exchange. Also, I'm taking a trip to China on next Monday 10-11, if you need to send it back do it asap with Priority Mail. I must receive it by the end of this week

[baccus61]

I finally tracked down the 1mm over-strike problem.

The new XL belts I bought last month don't fit the new XL pulleys properly. Grrrrrr!!!!
With all the tension on them it was hard to see the movement.
The trapezoidal shape on the pulleys wasn't deep enough for the belts to seat all the way into the groove and the teeth were riding on the bottom of the profile instead of the flanks. NOT GOOD !

I have now ordered another 2 new pulleys and 2 belts (1 spare) with the HTD-5 profile and 15mm wide.

These have a round profile and should fit properly into the groove.

I checked 2 of my other machines and they have the same problem with less movement than the laser table has but it is still there. I know what to look for now. Buying new sometimes isn't as good as you think.

**EDIT**
I put the machine back together with modified pulleys and a HTD-5 belt I had from a photocopier and I am still getting the 1mm over strike. I stripped the laser head down and rebuilt it and replaced another pulley and I am still getting the over strike. If I slow down the speed of the head to lower than 1"/sec then the over strike goes away. It must be in the mechanics but I can't seem to find the culprit. It's almost like a reflection of the beam in the mirrors is being split somehow as it is always the same size.
Time for a complete rebuild with THK linear slides and some new parts.
God this is frustrating!!!!
Rich.