Messages

41

General Mach Discussion / Re: Any one know how to build a cheap linear encoder?

« on: March 11, 2008, 12:22:54 AM »

If you have play in the lead screw and you use servo drives with the loop closed in the drive, you must be carefull of resonant feedback using direct coupled encoders. This is because the play in the lead screw can account for some encoder counts which the motors do not have direct control of.
I suppose a walk through the local scrap dealer might yield something too. You'de be amazed at what people chuck! Lots of equipment use linear encoders, like plotters and automation equipment.
The link you provided don't look like a 48" application, the inkjet hack could work on that, or are you building an upscaled model?

Whacko

42

General Mach Discussion / Re: Any one know how to build a cheap linear encoder?

« on: March 10, 2008, 06:32:37 PM »

Why does it have to be linear?

Whacko

43

General Mach Discussion / Re: Any one know how to build a cheap linear encoder?

« on: March 10, 2008, 06:16:53 PM »

Depends on the lenght. You can hack an inkjet printer. It has a high resolution film strip with lines and a sensor. But there is also a method to increase the accuracy of a home made linear encoder. But this will also be limited by lenght. Then you can use ferromagnetic strip from an old audio cassette, with spans of lenght. This can give you four channels. You need to pre record an accurate frequency on the tape, the whole lenght will give you about 500 meters. Then you can use the tape head with it's preamp for the signal. I've done this years ago to prove a pointless point to a hapless fellow!

W hacko...

44

General Mach Discussion / Re: CAPACITIVE DECOUPLING OF tHE 20KHZ SIGNAL

« on: February 16, 2008, 03:35:19 PM »

Dave, apologies for the absence, I included the Gerber cam files and pdf's of the artwork. I didn't see the thread.

Whacko

45

VB and the development of wizards / Re: Need to interupt while loop

« on: February 16, 2008, 03:18:48 PM »

Hi Scott, thanks for the input, but that won't work. I'm in a timer loop. Whilst in the timer loop, OEM buttons don't trigger an interupt in the kernell. I think I got the answer though. I didn't think of it but it has something to do with the button group.

Whacko

46

VB and the development of wizards / Need to interupt while loop

« on: February 15, 2008, 04:49:38 PM »

I am using a system key in Mach3 to interupt a while loop by monitoring a led state. The OEM buttons and OEMled's has a low priority in a macro while loop it seems. I have worked around it, but can't locate info on buttons that has a higher priority and is not assigned to Mach3 system. Is there available buttons for such an interupt?
I am monitoring a button/led while in a timer loop as to terminate the loop via external interupt premature to the timeout.

Whacko

47

General Mach Discussion / Re: Dwell interupt

« on: February 15, 2008, 03:52:37 PM »

Hi Zealous,

Wasn't me, I'm in Cape Town. There were two of em, jumped me as I got out the car. This country is becoming a health risk!

Whacko

48

General Mach Discussion / Dwell interupt

« on: February 13, 2008, 02:49:29 PM »

I'm sort of back on the forum. Got injured in a botched hijacking. The only good thing about it is the hijacker got of worse than me! Anyway, a question, is there a way of interupting an active G4P thread? With other words, while in the G4 dwell cycle, can it be stopped before timing out?

Whacko

49

General Mach Discussion / Re: CAPACITIVE DECOUPLING OF tHE 20KHZ SIGNAL

« on: January 22, 2008, 12:54:26 AM »

Hi Brett,

Walked straight into a mad rush 2008. Hope you folks had a fab christmas. I'm glad it's over in a way, I got tired of family and parties, till end of year yet arrives again.
I will be more regular on the site soon. We have some big orders, and projects, good for business. I'm also tied up in firmware development, so It's late night hours programming.

Whacko

50

General Mach Discussion / Re: OK that does it!

« on: December 25, 2007, 05:02:36 PM »

I'll have to get back to you a bit later, entertaining a sloshed family memeber

Whacko