3 Things You Should Consider When Choosing a Power Meter

April 27, 2015
Smart power meters can be used to show your real time electricity consumption, help with load management and transformer monitoring, and power monitoring.

Smart power meters can be used to show your real time electricity consumption, help with load management and transformer monitoring, and power monitoring.

Smart power meters can save you time and money since changes can be made to reduce energy usage automatically when it is not needed. Touch Screen PLC's, data loggers, Programmable Automation Controllers, and PC's running SCADA software can be used for control, monitoring and displaying the data in a way that is easy to understand and analyze.

So what are the most important things to consider when selecting an energy meter?

Single-phase or Three-phase
When choosing an energy meter, the first thing you need to consider is how many phases are needed for the system. Most suppliers nowadays provide single-phase power meters and three-phase power meters. If the current system you are logging data from is single-phase, then you need a single-phase power meter. If it is a three-phase electric system, then you can only use a three-phase power meter to work with it. Single-phase power meters like PM-3112 and PM-3114 are compact, din-rail mountable, and flexible for various energy monitoring applications. They come in 2 loops and 4 loops accordingly, and support a wide range of input types such as Vrms, Irms, kW, kWh, kVA, kVAh, kVAR, kVARh, and PF. They can be used in both low voltage primary side and medium/high voltage secondary side, enabling users to obtain reliable and accurate real time energy consumption readings from the equipment.

Number of Amps
After determining the phase of the power meter, another thing you need to consider is how many amps you need for the system. Usually, the most common options that intelligent power meters have for amps are 60 amps, 100 amps, and 200 amps. The number of amps supported can vary as the power systems vary. It is not workable if you choose a 60A power meter for a power measuring system that actually needs 100A. For example, the PM-3133 series three-phase smart power meter comes in three different types of amps: the PM-3133-100 supports 60A; the PM-3133-160 supports 100A, while the PM-3133-240 works for 200A. With their high accuracy (1%, PF=1), they can generate very reliable data on the actual power you consume. These compact size and cost-effective power meters are equipped with revolutionary wired clip-on CTs for easy installation. It operates over a wide input voltage range of 10 ~ 300 VAC which is compatible worldwide.

Communication Protocols
Smart Power Meters communicate over different mediums and protocols, so it is also very important to determine which communication protocol your power meter needs to work with. Modbus is one of the most common protocols in industrial applications. Developed by MODICON in 1979, Modbus has become a standardized, openly published and easy-to-use protocol to connect industrial devices. Smart power meters that support Modbus protocols are easier to integrate with your current Modbus systems. For example, PM-3112 supports Modbus RTU while PM-3112-MTCP communicates over Modbus TCP. Besides Modbus, other communication protocols are also available for power monitoring applications. CAN bus, or a Controller Area Network is a protocol that allows devices to be connected in applications without a hosting PC. Today CAN bus is used in automotive, cycling, industrial and entertainment industries for data communication. Smart power meters like PM-3133-240-CAN is designed to support CAN bus and can seamlessly integrate with existing CAN bus systems. Another protocol is CANopen, which is a communication protocol used in embedded systems in automation. Power meters that support CANopen include single-phase smart power meters like PM-3114-160-CPS and three-phase power meters like PM-3133-100-CPS. In conclusion, choosing a smart power meter with the right communication protocol is very important in getting the system up and running.

What Else?
Now that we have considered phases, amps, and communication protocols, what else do we need for a successful energy monitoring system? One biggest advantage of smart power meters is that it can be connected with SCADA and HMI software and automate the whole system. With the SCADA software, it can show the status of your equipment, send email or text message alarms, log data, implement control and generate reports. Touch Screen Controllers like TPD-433 can also be used for home automation projects where you can view your real time power consumption data and control your electronic devices on a touchpad.

>> For more information, click  here

Companies in this Article