| 摘要 |
PROBLEM TO BE SOLVED: To provide an exclusive method for a programmable controller which uses still only one keyword so that the management of the keyword is not made complicated, permits exclusive control over a communication between subsystems, and prevents illegal access from outside even if the keyword leaks. SOLUTION: The programmable controller is equipped with an I/O allocation table wherein the I/O address of a unit adjacent to a sequencer unit is set, a keyword storage part wherein the keyword for inhibiting illegal access from outside is set, a security object table wherein information specifying an object destination capable of accessing internal data of the sequencer unit is registered, and an access key table which contains an access key according to the information registered in the security object table; and the access key is sent to the object destination capable of access and connection permission is confirmed by using the access key and keyword. |
