Programmable controller

A programmable controller (PLC) that controls an industrial machine based on a user program, the programmable controller comprising:

• a detachable first storing unit in which first key data is written in a state in which a user is limited by a programming apparatus including a function limiting unit that limits the user, the first storing unit being protected from access;
• a second storing unit in which the user program is written by the programming apparatus in association with second key data;
• and
• a startup processing unit configured to execute startup processing for the PLC itself when a power supply is turned on, wherein
• the startup processing unit includes a startup-processing-stop determining unit configured to read out the first key data stored by the first storing unit inserted in the PLC itself and the second key data associated with the user program stored in the second storing unit and to determine, based on collation of the read-out two key data, whether the startup processing is continued or the startup processing is stopped for abnormal processing to be executed.