DIN3 by default can actually be considered a "Latch" for your RUN command provided by DIN2. DIN3-STOP can be considered a seal-in contact for 3-wire start/stop circuit. The following two statements are true, and should assist in clearing this up:
- If your DIN2-RUN contactor is a toggle switch (between 24v high or 0v low) it is not required to have DIN3-STOP connected to stop the motor; 0V to DIN2 will stop the motor in this case.
- If your DIN2-RUN contactor is a momentary button (a 24V pulse), you will need DIN3-STOP at 24v to keep the motor in motion; DIN3 reaching 0V stops your motor in this case.
Some documentation may display only STOP in documentation, and may lead to some ambiguity. This FAQ should clear up the true functionality.