Homing issue.

[cmdr114b]

I am at the testing stage of my K40 DSP conversion and all has been progressing nicely.
That is until I get to homing both the X & Y axis's(?) here is the issue I have:-

I have both the X and the Y travel working well and in the correct direction, both the homing switches are connected to their appropriate X- & Y- switch inputs on the controller.
From another thread I followed Marco suggestion and removed the lid of the controller and can see the correct LED's illuminating when either the X or Y switch is pressed so I am happy they are working.

If I position the X/Y carriage before I turn ON the K40 so that say the Y axis will hit the switch first then when I power on the unit the carriage moves both the X & Y axis towards the switches.
When the Y switch is hit the carriage backs off the switch and then touches the switch again and instantly moves to Y 169mm and X 58mm and stops. so the X axis never gets homed.
If I reset the unit so that at switch on the X switch touches first then the same happens but now the Y does not get to be homed.

I am expecting both axis to home and then the move to occur but this never happens.
I am really scratching my head on this one and would really appreciate some help.
Sorry if I have not made this very clear.
Thanks
John

[Techgraphix]

I think I understand the problem.. You can check which is the problem: controller or switches/wiring..
Disconnect both homingswitches from the controller and make a few wires from the controller to outside the cabinet
BTW.. are they microswitches or proximitysensors ?
Set your max speed to very slow (say 10mm/sec max) and place the head opposite of the homingpoint.
Then reset and connect the -Y wire to GND.
If the X stops homing, there is a problem in the controller... There is no setting to have it act different from homing both X and Y.
Reload the newest firmware could solve it??
If it works ok, you have to check the wiring or maybe a mechanical bounce that triggers the other homingswitch or even replace the homingsensors (if these are microswitches, I advice you to look for proximitysensors.. ) It can even be interference from other wires.. If there is no shielding......

Kees

[cmdr114b]

Many thanks for your quick response it much appreciated.
I am using Micro switches and I have used twisted pair for the connections back to the controller.
I can try your suggestion in the morning, its been a long day today.

I will get back to you when I have tried it.
I have never had to do a firmware update, I am using Ethernet to connect to my laptop, is there a utility to do this?
John

[Techgraphix]

is there a utility to do this?

No, it's just a matter of placing the UpgradeFile on a USB-stick, place it in the controller and download it into the controller..
What kind of controller you have?

Kees

[cmdr114b]

Its an AWC-608 controller.
That sounds simple enough.

Looking around here for files, the only one I can find is a patch file 150320V7.UG5, do you know if this is the right one?
John

[Tech_Marco]

It is the latest one I have. Make sure you clean up all files in the DSP before upgrade. Also, do NOT interrupt it during upgrade process.

You can test the home manually triggering the limit switches (need to do 3 clicks: YYX or XYY sequence). Make sure the laser head is located in the center so that it won't to the frame quick and without time to shut down. You can press "STOP" to stop it from moving

Marco

[cmdr114b]

Thanks Marco, I have downloaded the file and I will give it a try in the morning.
I will let you know how I get on.
John

[cmdr114b]

OK. I have spent all of the afternoon looking at this problem and finally found the answer.
After updating the firmware and doing all the suggested test to no avail I decided that it had to be the Controller.

As an electronics design engineer for the past 40 years I am very familiar with the type of faults that can occur on circuit boards.
So I removed the controller and removed the circuit board from its case.
Using a microscope I found three solder splashes across some of the DSP pins.
Two of these were ground pins so had no effect but the third was a short across the DSP input pins from the X & Y limit switch opto-couplers.
I removed the solder splashes re-assemble the controller and all now works as expected.

Thank you all for your assistance.
Many thanks
John

[Tech_Marco]

John, Great job!!

Sorry for the trouble and I'll complain it to the manufacturer for the quality control.
To compensate your time lost and the great effort, I'd like to offer you a coupon of $20 for your next purchase!

Regards,
Marco

[cmdr114b]

No problem Marco, I am just glad its sorted out and thank you for you kind offer.

You might like to also mention that it looks like they are using a poor solder profile during reflow, the job was obviously run and much too higher temperature for too long causing crystallised joints just short of being fully dry. This could cause you a lot of these sort of problems.
All the best
John

[Techgraphix]

We electronic-people tend to open things just to see what's inside...
Because of warranty-seals I didn't do that yet... but I think I have to ignore those seals... ssshhhht!
Good work!

Kees

[cmdr114b]

When it comes to returning things from Europe to the US I think we need to carefully consider our options.
If I can fix it then the time and hassle it saves is worth it especially when it also saves Marco the trouble of having to deal with it.
Thanks again for your help Kees.
John

[Tech_Marco]

Yes, no doubt about it


Marco