February 28, 2022
By Henry Smith, Design Engineer, Functional Devices, Inc.
Whether it is for tenant billing or monitoring power consumption of equipment in a building, sub-meters have been used for a long time and are becoming more common. Earlier this year, Functional Devices released a BACnet MS/TP, revenue grade, energy sub-meter – RIBPM413-BC. This week’s blog will provide an overview of this product and highlight some of its features and capabilities.
The USA Made RIBPM413-BC works with any UL or ETL Listed 333mV current transformer, like the ones we offer (CTA 1 Series), and it can be used on 3-Phase, 4-Wire or Single-Phase, 2 or 3-Wire systems from 120 – 277 Vac. It is only intended for Category III installations or less, which means it cannot be used in a Category IV installation. It is also capable of NET metering, which means it can differentiate between energy being generated or consumed by the load(s). You saw it right, that little “s” at the end of “load” means you can meter multiple loads (up to three) at once, with a single RIBPM413-BC. The Installation Guide explains how this can be accomplished.
The RIBPM413-BC has two on-board LEDs that provide some general information when viewing the unit, like a heartbeat blink, some energy usage information, and MS/TP communication status. Detailed information, however, is all transmitted over BACnet to the front end. A complete list of all supported objects can be found on pages 3-5 on the installation guide linked above, and the Protocol Implementation Conformance Statement (PICS) can be found HERE. All the measurement data is provided via Analog Input (AI) objects, and they range from line voltages, current, and frequencies to active, reactive, and apparent power.