| 摘要 |
PURPOSE:To prevent use of wrong teaching data by previously storing passwords in a password storing area provided in a nonvolatile memory and, at the same time, teaching data in a volatile memory and comparing contents of both password storing areas by means of a central processor at reading the teaching data. CONSTITUTION:Passwords are previously prepared and stored in a password area provided at part of the ROM area of a storage circuit 8. In addition, another password area is also provided in the RAM area of the circuit 8 and the same passwords as those prepared in the ROM area are set in the latter password area before the first teaching mode is started. Then the passwords in the ROM area are compared with those in the RAM area before the 2nd operation mode is started and, when they are the same, the operation mode is started by regarding the data in the RAM area as correct. When they do not coincide with each other, it is considered that the teaching data in the RAM area are destroyed and the passwords to the RAM area are reset. Then the mode is shifted to the operation mode after initializing the teaching data. Therefore, operation of a controller by means of wrong teaching data can be eliminated. |
