Which troubleshooting statement is false when the claw is closed and motor M1 does not start?

In the context of troubleshooting motor operations, the statement that sensor B1 should always be checked last is false. It is essential to check all sensors at appropriate points during the troubleshooting process, particularly because they are critical in confirming the operational conditions necessary for the motor to start. Sensor B1 plays a vital role by providing an input signal to the PLC, which directly influences the functioning of contactor K1 and, subsequently, motor M1.

When troubleshooting, following a systematic approach often involves checking input signals first, including those sent by the sensors. If there's an indication that the motor is not starting, it can be prudent to ensure that all necessary signals from the sensors are functioning correctly before delving into other components like the contactor.

The other statements are logically coherent within a troubleshooting context. For instance, if sensor B1 is not sending a 1-signal to the PLC input, it's appropriate to check contactor K1, as this could be part of the failure path. Similarly, if the PLC's input signal indicates that something is amiss, checking sensor B1 makes sense as it directly relates to the issue at hand. Lastly, dismissing the condition of contactor K1 entirely would not align with effective troubleshooting, as it is