So I have a 12V relay board that I used to use with my Arduino. It actually has two relays on it and I'm using only one channel. The board schematic is like the one shown in the image:
Since I wanted the relay to operate on an active high input, I tied IN1 and GND together. The GND here is also the LPTs GND. On the Vcc terminal where it says Arduino's 5V, I have pin 14 of the LPT connected. Across JDVcc and GND is an independent 12V supply.
Now every time I try to switch on the spindle, the relay clicks ON for a fraction of a second and then turns OFF and I see a 'Limit switch triggered' on the screen. Can anyone help me understand what is happening here?