Re: Home switch oddities

["David Volosky" <djvolosky-at-voyager.net>]

I reported on a similar situation that I encountered on a HP Vectra 133 /
using a FlexPort 42 for additional parallel ports.

I had OMS MD10A stepper drives connected the parallel port and was using the
Bridgeport I/O. No switches were installed. Everything was working as
expected.

I began to experiment with the program code ( M codes ) and I started to get
errors. This was on a program that ran prior to the coolant being turned on.
I went through the gyrations of changing switch polarities, etc. , for a day
or so. The final fix to this was to terminate all active, unused pins on
both parallel ports. I used 10K resistors tied to the 5 volt supply for
pull-up's on the parallel port pins.

I don't have any experience with the STG products. The symptoms sound the
same. Try terminating all unused I/O pins ( either high or low ).

Dave