What does it mean that there is a short wire at the terminal of the inverter control circuit?

These short-circuited terminals are generally functional terminals such as internal interlocking circuit, emergency stop, STO or frequency converter enabling, and these terminals will be short-circuited in most use cases (most of them do not need these functions).

The internal interlocking circuit is used to interlock the operation command with the operation conditions and maintenance status.

Emergency stop, as its name implies, is an emergency stop, which exists as a safety function.

STO is a safety torque terminal and a safety function defined by standard IEC.

Enabling is usually a prerequisite for startup.

But our general application is only start signal and stop signal, so these paragraphs must be short, because they are all advanced and effective.