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.
Some documentation may display only STOP in documentation, and may lead to some ambiguity.
The following two statements are true, and should clear up functionality:
- 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.