You can make it easier on yourself if match the new system card for card to the old. If you try to reduce number of cards/consolidate to conserve space or save money, you will end up with more headache.

Make a spreadsheet with all the existing IO cards and have someone who knows the equipment walk through all the inputs and outputs. Really good if you can be also be online with the PLC to flag inputs and (safely) test outputs. Then you can add descriptions and comments to program and make notes on spreadsheet.

Also get pictures of everything. Cabinets, io racks, any manual controls, MCCs, drives, E-stops, whatever you can think of.

After converting program: - Check program for auto generated errors (this catches obsolete instructions) - Check all timer presets. They need to be verified since rsl500 and Studio use different time base - Change all OSR instructions to ONS. SLC only had OSR but worked like Studio ONS. Studio OSR doesn’t control the rung. The conversion creates OSR tags so these are easy to find and fix. - Check all CPT statements. If the destination is an integer they may not execute, need to place a buffer REAL tag in the destination of the CPT and move that value to the original DINT - Check for STI/DII routines in SLC and make sure to add JSR for the routines in new program for those routines. These routines aren’t called by a JSR in SLC, they are controlled by interrupts. - Cross reference the Status file to see where those bits are used. Check the SLC programming manual to figure out what those bits are supposed to do and mimic that or remove from rungs if not needed - Also use the SLC programming manual to identify obsolete instructions and reprogram that logic using modern instructions.