Let's do it like this, C.P.:
This way, everybody can see what I'm talking about and offer suggestions, if they have any.
Here's the relevant page from the Syren50 'Owner's Manual', showing the various DIP switch positions for 'Analog' mode. That's opposed to a computer control of the board. I'm pretty sure that my board is set up in Option 1, Analog Bi-direction. If so, I'm going to try Option 3, Analog One-direction with forward/reverse select on S2. Right now, to increase my speed, I turn the potentiometer clockwise. I suspect that, when I alter the DIP switches, I'll have to rotate the pot counter-clockwise to increase speed. That won't work, the way my control stand is built. Here's what I think I could do to correct that: If I reverse the polarity on the pot, it should work.
So, here is the way it's wired right now.
To reverse the polarity to the pot, I'll just reverse the power supply wires at the terminal block, like this:
That might also cause the reversing toggle switch to 'face' the wrong direction, but that's easily fixed. There is plenty of slack in the wiring, so I'd just loosen the nut, and rotate the switch 180 degrees.
All this rigmarole is assuming that changing the DIP switches gives me a '0 volt to motor stop' Fail Safe, which is what I'm after. Anybody else feel free to offer insight or suggestions.
Mike
Former Locomotive Engineer and Designer, Sandley Light Railway Equipment Works, Inc. and Riverside & Great Northern Railway 1962-77
BN RR Locomotive Engineer 1977-2014, Retired