For the purposes of this article, we will refer to the 7200/7300 family of meters as the "virtual element" (VE) style meters.
Virtual vs. Non-Virtual Meter Elements: What’s the Deal?
If you’ve ever tried to integrate a power meter and found yourself knee-deep in Modbus IDs and register maps, you’re not alone. One of the most common points of confusion? The difference between “virtual” and “non-virtual” meter elements and how their data point mapping differs. This article will help break down those differences.Series 7000/7100 Standard Elements
These are your classic, physical meter elements. Here’s how they work:- Element Count: Depending on the model, you’ll get anywhere from 1 to 16 elements. Each element has up to 3 CT landings for monitoring an energy load or source.
- Quick Math Trick: Take the last two digits of the meter's part number (say, 71d12), divide by 3 to calculate your total number of elements.
- Modbus RTU IDs: The base Modbus ID# you set in the meter corresponds to Element A. Each additional element gets the next ID up (B = base+1, C = base+2, etc.).
- Modbus TCP: Things are simpler here—ID#1 always starts with Element A, no matter what.
Virtual Element Meters (7200/7300 Series)
Here’s what makes them unique:- Element Count: Up to 24 virtual elements can be created with flexible use of each individual CT input on the meter, allowing for combining up to three CTs to one element.
- Modbus-Only: These meters are designed strictly for Modbus RTU or TCP.
- Single Modbus ID: Unlike the standard meters, all virtual element data lives under one Modbus ID#.
- Simplified Data Points: Each virtual element only gives you the essentials—Energy, Power, and Power Factor. That’s it. You’ll find these in the register map under the “virtual element” sections.
- Voltage References: The meter circuit board and terminals will have two sets of voltage reference landings, but only the first set is usable when you’re working with a virtual element meter.
Summarizing The Differences
| Feature | Series 7000/7100 | Series 7200/7300 |
|---|---|---|
| Modbus ID# | One per element (A, B, C...) | One for all virtual elements |
| Data Points | Advanced data set of per element and per phase measurements | Energy, Power, Power Factor only |
| Protocols | Modbus RTU and TCP BACnet MS/TP and IP | Modbus RTU Modbus TCP |
| Voltage References | Two services with three phases or less | One service |