Mitsubishi inverters are popular among users due to their reliable quality, small size, and lower price compared to European and American brands. Our factory uses more than 30 Mitsubishi inverters. We encountered some problems during installation and commissioning, which are described below using Mitsubishi F50 and A540 series as examples: 1. Parameters cannot be written The reasons why parameters cannot be written are generally as follows: (1) The external operation mode is not in the PU operation mode. The solution is to switch the operation mode to the PU operation mode or set the Pr. 79 operation mode to "1". (2) The running signal is not released, that is, STF (or STR) is in the "ON" state. The solution is to make the running signal STF (or STR) in the "OFF" state. (3) The "Parameter writing prohibition selection" of Pr. 77 is set to "1". The solution is to select "0" or "2". (4) The time of pressing the SET key is too short, less than 1.5 seconds. The solution is to press the SET key for more than 1.5 seconds after the parameters are written. (5) Parameters other than the set parameters. Users generally do not need to modify these parameters, or set Pr. 160 to "0". 2. When a run signal is given, the motor will start running immediately without speed adjustment. The reason for this phenomenon is that the start and end wires of the external speed control potentiometer are reversed. When the potentiometer is set to "zero", it appears that no speed is being applied, but in reality, the maximum speed is being applied. Therefore, the motor will start running immediately upon receiving a run signal. Simply swapping the wires at both ends of the speed control potentiometer will solve the problem. [b][align=center]For details, please click: Problems and Solutions in Mitsubishi Inverter Debugging[/align][/b]