I am trying to backup a program on a Micrologix 1200 PLC, without any success. I am using RSlogix 500 software and serial connection. I have configured the driver in RS lynx to DF1, but when I click on auto configure, it fails. Also I cannot see it when I browse.The plc is connected to an HMI , and I have noticed there is a button on the front, just below the comms port. Does anyone know what this button is for, its identified as comm. I have heard that when the button is pressed it toggles between default protocol and the protocol that the HMI requires. Can anyone confirm this.