Shared display generally relates to a CRT based Operator Station where there may be many Operator stations in one location or in various locations. A Flow Controller for example may be called up on any of these locations ie: Shared Display.
Board I assume for example, you would mean a...
Running both your PLC input and Recorder in a series loop is going to be the most cost effective, however should in the future you require to disconnect a device for any reason you will lose all components in the series loop.
A signal transducer as suggested by dcasto is likely your best...
