PLC (Programmable Logic Controller) control-based test current instantaneous switching method

The present invention provides a PLC (Programmable Logic Controller) control-based test current instantaneous switching method. The method includes the following steps that: a PLC obtains an instantaneous switching instruction for a first relay and a second relay through a touch screen; the PLC controls the first relay to be switched on for a preset time and the second relay to be switched off according to the instantaneous switching instruction, obtains the voltage value and current value of a 6-times current closed circuit through a measuring instrument module; after the preset time ends, the PLC controls the first relay to be switched off and the second relay to be switched on, and obtains the voltage value and the current value of a 1-times current closed circuit through the measuring instrument module; the PLC performs calculation according to the voltage values and current values so as to obtain power and a power factor and displays the voltage values, current values, power and power factor in real time