Control Box Communication Problem

[dan@roadcase.com.au]

Hi,all.
Am having difficulty getting my PRT alpha to run continuosly. I keep getting a pop up window saying: "Missing Comm Return. Hit OK to attempt to continue".

This message is usually being triggered after a part has run and command so,1,0 is used before it moves to another location. To make things more frustrating it doen't do it all the time, I can restart and run the same part again and will be fine, sometimes!!

Wondering if it is to do with the serial to USB adapter converting??? Has anyone else had this problem??? Is it possible to run the alpha control box on a serial cable from the computer thus bypassing the converter all together???

[sawdust47@msn.com]

Hi Dan, I had a problem on & off on my alpha , I changed computer , grounded everything, it would go away & come back , sometimes the pop up window " stop switch wired wrong" it got so bad even restarting didn't help , I opened the control box & turned it back on with door open & found the top Right contactor was not pulling in the way it should (was pulling in cocked)(THE WHITE BAR ON THE CONTACTOR) I shut off the power to the control box & pushed the white bar in & it would get stuck in , it should move freely, shopbot sent me a new 1 last week & problem solved Hope this helps

[grant]

Dan, it sounds like you may be experiencing a problem related to electrical noise, especially if you have a single phase Colombo spindle. The first thing we usually try to see if this is the case is to remove the emergency stop from it's four screw terminals, marked on the board as ES1, ES2, ES3 and ES4. Naturally, you will need to be careful while doing this, the power should be off and all operators and potential operators should be made aware that the E-stop is non-functional. In place of the E-stop, make a jumper connection from ES1 to ES2 with a short piece of wire, and do the same from ES3 to ES4. Then, you can restart the control box and try your file again. If this fixes the problem, call and let a technician know, they can get some capacitors in the mail to you that should fix the problem permanently.

Regards,

Grant Bailey
ShopBot Tools Inc.

[richards]

Dan,
I replaced the USB to Serial Bridge cable with one purchased from the local BestBuy store (Dynex brand at $30-$35). Since then the 3hp Colombo has performed flawlessly.

Before replacing the USB to Serial Bridge I ran shielded cable to all inputs and ran additional ground cable between devices. In fact I was almost to the point of replacing all sensor/switch wiring with fiber optic cable, which would have required significant time and expense, when I realised that almost all errors were Comm errors of some type - which were handled by the new USB to Serial Bridge.

[gerald_d]

Did Dan solve his problem?