Thus, those of the 72 kinds of parameters assignable to the white switches TCSW7 and TCSW8 which have fixed values are stored in the ROM 130 as the parameters TCPW(1) to TCPW(64), and those of the 72 kinds of parameters which can be modified are stored in the RAM 129 as the parameters TCPW(65) to TCPW(72).