Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: mbwittig on June 18, 2007, 12:42:54 PM

Title: cannot get encoder or mpg to work, need help
Post by: mbwittig on June 18, 2007, 12:42:54 PM

I took a 6 volt battery and hooked it up to the +5 and ground lines of the encoder (the encoder says 6V is within the range spec for it btw).  I connected the A channel to pin 10 and B channel to pin 11 of the parallel port.  When I turn the encoder I dont get a reading.  After setting the pins in the config screen the reading is simply -1 and doesnt change.  What am I doing wrong?  I tried 2 different encoders with the same result.

Title: Re: cannot get encoder or mpg to work, need help
Post by: Chip on June 18, 2007, 01:20:09 PM

Hi, Mbwittig

Did you connect the Neg. to a known good Gnd pin on your interface Cable ?

Maybe this is It, Chip

Title: Re: cannot get encoder or mpg to work, need help
Post by: mbwittig on June 18, 2007, 01:47:05 PM

OK so I have to run a wire from the negative terminal of the battery to a ground pin on the parallel port?

Title: Re: cannot get encoder or mpg to work, need help
Post by: Azrael on June 18, 2007, 05:31:58 PM

Off course you have to connect battery gnd to the lpt pins 18 - 25, as this is the way of closing current loop.
Cheers

Title: Re: cannot get encoder or mpg to work, need help
Post by: Chip on June 19, 2007, 01:05:53 AM

Hi, Mbwittig

Yes neg. to Gnd, Not all cables or PPort cards use all the 18-25 pins, If your using a brake-out board all are probably tied together on the board though.

Thanks, Chip

Title: Re: cannot get encoder or mpg to work, need help
Post by: W.Jansen on June 20, 2007, 06:24:58 AM

Hi all

Will 6 volt not destroy your port if no precautionary measure is taken?
If i want to put an encoder directly to the port do i need to put a resistor in series with the a and b channel?

Greetings:
Willem

Title: Re: cannot get encoder or mpg to work, need help
Post by: Chip on June 21, 2007, 01:24:46 AM

Hi, Willem

The 6 volts isn't connected to the port, Just the Gnd/Neg, A and B outputs thay should be 5 volts from what i've seen.

Thanks, Chip

Title: Re: cannot get encoder or mpg to work, need help
Post by: W.Jansen on June 21, 2007, 02:24:09 AM

Hi Chip

My mistake , the output signal is of course stabilized.
Bud how about a resistor in series with A-B , shall that be necessarily and if yes what value should it have?
I ask this becourse my intention is to use two encoders for MPG purpose and i dont like to add a seccond break out board.

Greetings:
Willem

Title: Re: cannot get encoder or mpg to work, need help
Post by: Chip on June 21, 2007, 02:25:33 PM

Hi, Willem

If there 5 volts no resistor needed, some TTL encoders require a pull-up resistor, I think theres a good description on the Rutex web site.

There tied to the A & B lines then to 5 volts, Around 470 ohm's, Hears the link to look at.

http://www.rutex.com/pdf/R9xHbdi.pdf

I've used two encoders also, Direct to port.

Hope this Helps, Chip

Title: Re: cannot get encoder or mpg to work, need help
Post by: W.Jansen on June 21, 2007, 03:01:53 PM

Thanks Chip

I take my chance and give it a try , in the worst case it can cost a lpt board.


Greetings:
Willem