ABSTRACT
We are using RS-485 networks for interfacing remote utility meters located throughout the campus to two of our metering computer servers. RS-485 is used because it allows addressable communications with up to 32 meters on each leg, using a two-wire connection. These meters communicate using MODBUS RTU protocol by means of the Intellution-FIX MBS software driver. The Central Building Utilities Metering System (CBUMS) server accepts inputs from 200 Power Measurement, Ltd. (PML)-3300 electric meters divided into seven networks. The medical school area server called MED_MAX accepts inputs from 80 PML-7300 electric meters in 8 networks. The telephone center is located in the basement of Kline Biology Tower. KBT is located about 3000 feet north of the central area hub at Woolsey Hall. The science area meters are located less than 4000 feet from the KBT hub. Both single and dual channel versions are used to monitor both chill water and condensate flow.
