Sinking or Sourcing: Matching a PNP Sensor to the Input Card You Have
PNP sensor wiring is decided on the input card’s spec sheet, and almost nobody reads that row. Under Voltage category, a 1756-IB16 says 12/24V DC sink and a 1756-IV16 says 12/24V DC source — same form factor, same 16 points, same 5V off-state threshold, and only one of them will ever see a PNP sensor … Read more