kexlington
Member
Hi,
I have a very old machine I am trying to fix. The PLC is an FA-2 Junior and I am able to connect to it and monitor the code using WinLDR.
Luckily for me, there are no comments in the program and I just have a heap of memory addresses. While trying to reverse engineer what is going on, I have found a number of memory registers that change during the course of the machine operating, but when I do a cross reference on these registers results are returned but there is nothing writing to the registers - all results are read only. I really need to find out what these registers do - they appear to be related to the sequence that machine operates with.
This machine is old - there is no HMI or SCADA writing to these memory registers (there's no network connection to the PLC at all). The memory registers must be getting written to somewhere in the program, but I can't find where. Having ~400 rungs of uncommented code doesn't help.
Has anybody out there had this experience while using WinLDR?
I have a very old machine I am trying to fix. The PLC is an FA-2 Junior and I am able to connect to it and monitor the code using WinLDR.
Luckily for me, there are no comments in the program and I just have a heap of memory addresses. While trying to reverse engineer what is going on, I have found a number of memory registers that change during the course of the machine operating, but when I do a cross reference on these registers results are returned but there is nothing writing to the registers - all results are read only. I really need to find out what these registers do - they appear to be related to the sequence that machine operates with.
This machine is old - there is no HMI or SCADA writing to these memory registers (there's no network connection to the PLC at all). The memory registers must be getting written to somewhere in the program, but I can't find where. Having ~400 rungs of uncommented code doesn't help.
Has anybody out there had this experience while using WinLDR?