Control apparatus and control apparatus system

A control apparatus system comprising:

• a non-transitory computer-readable recording medium storing:
• additional software additional to a program of the control apparatus system, the additional software comprising software identification information;
• recording medium identification information;
• and encrypted information generated by encrypting the software identification information, using the recording medium identification information as a key;
• and
• a programmable logic controller connected to the recording medium, the programmable logic controller comprising:
• a storage;
• and
• a controller capable of accessing the recording medium and the storage, the controller configured with installation software to perform operations comprising:
• obtaining the encrypted information from the recording medium;
• obtaining the recording medium identification information from the recording medium;
• obtaining decrypted software identification information by decrypting the encrypted information, using the recording medium identification information as the key;
• obtaining the software identification information from the additional software;
• comparing the decrypted software identification information and the software identification information obtained from the additional software;
• storing the additional software in the storage when the decrypted software identification information agrees with the software identification information obtained from the additional software as a result of the comparison;
• and
• deleting, after storing the additional software in the storage, the encrypted information, the recording medium identification information, and the software identification information, from the recording medium and from the storage, wherein the additional software is rendered usable only when the recording medium storing the correct encrypted information is used based on the comparison between the decrypted software identification information and the software identification information from the additional software.