This isthe PROM/RAM card for the Low Level PIU.

The RAM on this card is used for the PIU database. The PROM is used to store microprocessor program instructions and constants used in process algorithms.

This card has 16 edge-mounted LEDS to show status and error messages concerning the LL PIU.

In order to be compatible with the Hiway Gateway on an LCN, this card must have a hardware revision of 'N' and a firmware revision of 'J'. Boards with hardware revisions prior to 'M' and firmware prior to 'H' have a problem in the open thermocouple detection circuitry. WPC ships only LCN-compatible revisions of this PROM/RAM board.