I just set up a CNC4PC solid state relay board. Basically I wired the board into two duplex receptacles, added the 5v power supply, blah blah blah. So the board seems to work fine - turns the appropriate receptacle on and off when the keys are pressed in Mach.
My question/issue is this: the input signal to the board is an active low. The problem is that when you disconnect the board from the parallel port - or turn the computer off - the relays then all close. I found this out this morning when I shut the CNC computer down and the spindle on my mill promptly jumped to speed. Not exactly the most soothing occurance.
Did I do something wrong in my wiring? Is this normal for an active-low output? Anyone used this board and faced this problem?