Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: generatorlabs on August 16, 2009, 08:35:07 PM

Title: Axis Outputs OK but inputs=no go
Post by: generatorlabs on August 16, 2009, 08:35:07 PM

I have been using my table without e-stop or limits since I built it a few month ago. Now that I have ironed out any kinks I have begun to complete the machine. The axis outputs work great however I cannot get the inputs to work.

My driver board has a DB9 connector for the four input triggers. These inputs are sent via opto isolators to pins 10-13 on the db25 connector. I have verified the operation of the limit switches with a meter. With the PC powered up and with the switches open I read 5 volts on pins 10-13 (with respect to pin 25 ground). With the switches closed I read close to zero on the same pins. Mach 3 however does not seem to recognize that there are inputs connected. I am watching the indicators on the diagnostics page. I have enabled the home/limit inputs via "Ports and Pins". Is there something else that I am missing here?

Your help is greatly appreciated.

Title: Re: Axis Outputs OK but inputs=no go
Post by: Chip on August 17, 2009, 01:25:09 AM

Hi, Generatorlabs

Probably just need to change the Active Low "State" and may need to use the Homes & Limits page to change the Home Direction also.

Chip

Title: Re: Axis Outputs OK but inputs=no go
Post by: generatorlabs on August 17, 2009, 07:19:42 PM

I attempted to set all the inputs for limit and home to "Active Low" with no result. With the parallel cable removed from the driver board I can measure 4.7 volts on pins 10-13. I even tried to jump pin 25 to pins 10-13 with a 470 ohm resistor to bring them low and found no response within the on-screen indicators.

If I use keyboard emulation I can see the indicators toggle so I know the program is working. I am having a dilemma with the response of the real world limit switches. Could I be looking at a funky parallel port or is there something else I am missing here?

Title: Re: Axis Outputs OK but inputs=no go
Post by: Chip on August 17, 2009, 09:27:35 PM

Hi, Generatorlabs

Verify that pin 25 is actually a gnd pin, Not all printer port and cables use all pin's 18-25, I usually jumper pin's 18-25 together at a common point,

The 470 ohm resistor isn't necessary as the input's can be hard grounded.

Try this free printer port program ton test them also. http://www.geekhideout.com/

Chip

Title: Re: Axis Outputs OK but inputs=no go
Post by: generatorlabs on August 18, 2009, 08:15:00 PM

To begin, a million thanks for the link to the Parallel Port Monitor. It works like a charm. In fact, it works so good that it proved what a butthead I am. All along my port was fine. In my ignorance I assumed the Zero in the "Ports and Pins" screen was indicating the first parallel port (sort of like how SATA drives do) and I left the default value in there. I was only changing the pin numbers.

So I bow in humility and thank you  :-\

Title: Re: Axis Outputs OK but inputs=no go
Post by: Chip on August 18, 2009, 09:35:27 PM

Hi, Generatorlabs

Well don't feel bad, Weave all done that and have the T-Shirt to prov it, Just put it in the Closet with the rest of them.

That's what I Do, Chip  :D

Title: Re: Axis Outputs OK but inputs=no go
Post by: RICH on August 18, 2009, 11:06:35 PM

Hey Chip,
After the first dozen the shirts come in diferent colors, man i hated the pink ones!  ;)
RICH

Title: Re: Axis Outputs OK but inputs=no go
Post by: edvaness on August 18, 2009, 11:50:04 PM

Rich,

Send the pink ones to Hood. They go good with his skirt.  ;D

Ed