Omron PLC Programs Protection from Being Downloaded

Protecting your PLC program from being edited or downloaded is one of the main concern in some of the important project. So if you are not using PLC protection option to set or release PLC password, then you can use a PLC instruction to protect your PLC program from being edited and downloaded. Subscribe to Automation-Talk by Email.



For protecting our program we use a simple instruction called FUN(49) with AR memory area. Note that this method can not be used for PLC not having AR area. Some example of PLC with AR area are CPM1, C200H, C200HS, C1000H, C2000H, CQM1, C20P, etc. Main function of FUN(49) is to protect the PLC program and when switch to RUN mode it act as monitor mode.



To protect your PLC program just add a NO contact in Rung 0 with address AR10.01 and after that add instruction FUN(49) with below syntax.

Syntax FUN(49) Instruction

[FUN(49) 0 0 #Password]

Below is the sample PLC program for reference.