Returning the SLC 5/03 Processors to Initial Factory Conditions

I have SLC 503 CPU which i am not able to access because of a password (there is no way to get this password) and
it is having a fault, I have the original program with me and I am thinking of resetting the CPU to its factory setting and then transferring this original program to the CPU, but before i do that i read in the manual that

If you return the processor to the initial factory conditions, the communication
configurations are returned to their default settings and the user program is
cleared.

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I am worrying about the Communication settings, There is an HMI here, if i reset the CPU to factory setting and download original program to CPU will everything work,are communication settings also a part of the Program.

then transferring this original program to the CPU

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Compare the program you have with default, you should also be able to find the COM settings in the HMI and make sure they are the same as the PLC

If you have the original program why is it password protected?

The guy who put the password forgot it but he was able to provide program from another PLC which is also the same, they use the same program for all the standard system.

You can short out the 2 spots on the processor to reset to default
Youtube: https://www.youtube.com/watch?v=nOixu-st1Ko

Clearing memory from an Allen Bradley SLC 500 Including Passwords

I am aware of the process to reset .However after reset how do i restore the communication settings because i have the original program but not details of how the CPU commnication is configured.

comm's settings are a part of the program as long as the back up you have was the same as the one running

Once processor is reset to default and new program is loaded it will prompt you that comms is different and ask if you want to accept new configuration, say yes to put back the comm's from original program.
As far as programming it I would use the RS232 df1 and auto configure in RS LINX to get communication with the defaulted processor then load the program back in

Also... most of the HMI's will tell you in the setup screen what the COM settings are so double check there to make sure your program has the correct settings

qwemx said:

I am aware of the process to reset .However after reset how do i restore the communication settings because i have the original program but not details of how the CPU commnication is configured.

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Everything (ladder logic, data files, communication settings) gets downloaded, but there is that warning to apply the changes and also the possibility that the file you download is not the most current and some of those settings got changed. Just answer yes when prompted to apply the changes and at least then you will know what they are and can go from there if you have further problems.