How to Reset a M580 CPU

[Trinxs1]

When an M580 CPU has an Application Password (which you do know) which is preventing access to the CPU there is a way to clear the password so you can regain access.   

If the CPU is a hot standby module, power down the rack, change the rotary switch on the back of the module to reset, replace the module, power up the rack and CPU wait for approximately a minute until the LED pattern is steady, power down the rack, change the rotary switch back to either A or the B setting, replace the module back into the rack and power it up again.   The module should now be in the default state.

if the CPU is a standalone module, power down the CPU / rack.  Place the module in slot 1 NOT slot 0.  Power up the rack and wait approximately a minute until the LED pattern is a steady pattern.  This effectively should be a reset state.  Connect to the module via USB download a valid application.  Power down the module and move the CPU to slot 0.   You should now have a CPU that you can connect to.

If the CPU is a standalone safety module the steps are similar.  Power down the rack.  Move the co processor to slot 0 not slot 2, move the CPU to slot 2 not slot 0.  Power up the rack.  Connect using the USB programming cable and download a simple configuration project for the PLC.   Make sure it downloads.  It will say not successful, make sure you obtain a response.  Power down the rack.  Move the CPU to slot 0, move the coprocessor to slot 2 and power up the rack again.  You should be able to connect to the PLC and download an application without the need for a password.  It may require that you press the enter button but keep the password area clear. 

These steps can be used to reset access so a new program can be loaded.

This was tested with a CPU of V3.21.  Updated 2025-04-07.

If you wish to recover the project in the CPU but you do not have the password.  Try to connect to CPU using USB , when the window prompting password entry appears press the "Shift"+ "F2"  buttons at the same time.  This will generate a long string of characters which you must copy.  The string sequence will be used by the global level 3 technical support team to generate a one off recovery password.  When you have this password you will be able to access CPU and download the project.   A technical support case must be raised to do this and the response time will vary depending on when the case is raised, it may also require a statutory declaration that you are authorized to do this.

Please also note that in some cases such as when a CPU has failed this process may not work.

Another approach that is worth considering is to insert a memory card into the CPU memory slot that has been configured with a simple configuration for the same CPU model.  On start up the CPU will read the card, detect a difference in program and overwrite the project in the CPU memory.   

To clear the program from the CPU.  Select the PLC option from the menu / backup / clear backup.  Exit the program and do not save the application.  Power down the PLC, with no backup the PLC program will be cleared, as per factory default.

Trinxs

[Rodrigo_Garcia]

Thanks for sharing!

[Rodrigo_Garcia]

Thanks for sharing!