I have a legacy A2N-CPU utilizing a A1SJ7C24 serial communication module to exchange data to a VAX.
Can someone explain to me how I can access the data registers necessary to view the data in those registers that are being sent through the serial comms?

Also, how does this PLC convert these binary tables to ASCII? I cannot see any ladder logic that does this. I am using GX developer software.

 

I have a legacy A2N-CPU utilizing a A1SJ7C24 serial communication module to exchange data to a VAX.
Can someone explain to me how I can access the data registers necessary to view the data in those registers that are being sent through the serial comms?

Also, how does this PLC convert these binary tables to ASCII? I cannot see any ladder logic that does this. I am using GX developer software.

I need to provide more specifics.
We have a 1989 vintage Murata Wiedeman Turret Punch Press that utilizes GE FANUC controls for all of the operations of the press. There is a serial comms connecting it to a VAX in the computer room. This is how it receives the part-punch programs via a DNC program. This communication is one way; the press only receives messaged.

The automated loading of the sheets to be processed is controlled by a MITSUBISHI A2N-CPU. This PLC also communicates to the VAX in the computer room over serial comms.
The VAX receives messages such as WD0001 from the PLC, which is the SHEET READY signal for the initiation of various processes and programs to compile data, then pass that data to a mailbox in which the DNC resides. This is then passed to the press for punching the product.

The PLC apparently, somehow, also maintains communication with the FANUC in the press. The PLC is then responsible for passing press status messages to the VAX, such as alarms or warnings.

This is where I get stuck. I understand HOW the messages are converted from BIN to ASCII...but I just don't see that I the program. What am I missing?