''repair of abb plc''

It's incorrect request as it should be better detailed. On the one hand if (to suppose) ABB controller had been part of complex machine manufactured by third part vendor --- it's unlikely you can simply replace ABB PLC and plant there Allen Bradley one instead. It's unlikely as simply you do not posses program which has to be uploaded there.

On the other hand if your controller governed system had been completed, assembled and programmed on site by your personnel and your administrative staff had decided to change brand they use for processing you're free do this work. To this point --- all controllers are compatible. But you are to be replace also not only PLC but control modules due to inevitable incompatibles of data protocols and other like things.

Do not be reckless if you going to replace CPU's i.e. chips. It's simply reckless even for the same brand modules.