USB-Parallel port converter for an MPG/Pendant?

I know its been asked a thousand times if a USB-Parallel converter can be used as an output device to drive step/dir drives, and the overwhelming answer is no.

But I did some searching and can't seem to find if its possible to use one as an input device, because I just picked up an MPG4 6 axis pendant (www.cnc4pc.com/Store/osc/product_info.ph...h=40&products_id=162) and a C22 pendant interface card (www.cnc4pc.com/Store/osc/product_info.ph...h=40&products_id=159) for dirt cheap from ebay.

It seems to me that since my mainboard doesn't have a parallel port, that if possible to use a USB converter that it would definitely be the easiest way to fly.

My mill already has an atom 1.8 mobo, PCI 5i20, 7i37TA and two 7i29 servo drives. Because of space limitations and form factor I don't have any additional PCI slots, unless theres a way to split one PCI slot into two. If I can't use a usb converter I do have another open I/O port on the 5i20, but I'd be interested to know what the easiest way to interface the pendant to my machine.

I dont know how you would read the the pins with a USB-parallel converter, but it might be possible for low speed inputs. I suspect it would not work well for the MPG quadrature inputs however, as these must be sampled at least 400 times a second to track a one turn per second rotation of the MPG.

You should be able to wire the pendant directly to the 5I20 GPIO pins however, at a 1 KHZ servo thread rate you should be able to track the MPG to about 2 turns per second. If this is not fast enough, the MPG could be wired to encoder inputs on the 5I20

Hi

I think trying to convert a DB25 plug to USB and then convert back somehow to use as I/O is incredibly convoluted.

If you have I/O available on your Mesa board, I would look at cutting the DB25 plug off and wire it straight in.

It is rather peculiar that it requires an interface board to connect to a parport. My home made pendant has all the same controls and just plugs straight in.
I suspect that is because there is no provision for power for the MPG, whereas I spliced in a usb cable to provide the 5v required on mine.

I am sure PCW, Andy or cncbasher will be able to advise on the specifics of connection

regards

Looks like PCW beat me to it