Bad Breakout Box, Encoder Error, or other?

Electronics
1

I am in a bit of a tricky situtation with a DIY machine that is throwing me errors. Essentially, what we have is two groups of rotary encoders that send signal which then get read by our software. Essentially, turn dial and on screen I should read position.

The encoders signal goes through a DB15 breakout before going into an actual DB15 cable, that feeds into a DB15 female input before being read by the machine. This input is protected using self-resetting poly-fuses.

The DB15 breakout we use has both a male and female receptacle. Normally, we use a male to male pass through cable for our connection. However today, I used hooked up a female to male cable, and now do not read any positions. When I switch back to the male to male cable, I also do not read positions.

I’m a little concerned, because switching cables should not have done anything. A breakout should send the same signal to the same numbered wire, regardless of cable type, right?

2

To figure out what happened you will want to find the schematic for the breakout board and/or the schematic for the computer side’s DB15 and draw your own ‘schematic’ of what happened when you put in the wrong cable vs when you used what’s the correct cable/adapter.

If it was just TTL 5v stuff it normally is pretty tolerant of short circuits to ground. But if there’s both 5V and RS232(12-15V) signals then there could be some circuit damage done. Show us your connector pinout listing all signals on all pins and we might be able to help.

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