Mitsubishi PLC SET RST mainly operates bit elements inside plc, such as M, Y, etc., in pairs.
SET: Set the operating digital component to 1 , which can be understood as being switched on.
RST: Reset sets the operand component to 0, which can be interpreted as a break.
SET M56 can be understood as switching on M56.
The RST M56 can disconnect the device M56.
SET Y000 Y000 is connected to the com port.
RST Y000 Y000 is disconnected from the com port.