Machine Control; Structural and Physical Test and Monitoring
Monitoring and recording multiple parameters of metering, energy, demand and power quality at the same time to ease the fault tracking in the system besides performing real time analysis.
Making full use of the NI LabVIEW, a portable and user-friendly monitoring system that record multiple data from the power meter, in addition to performing real time analysis on various parameter.
Metering is always needed in the field of engineering to perform the analysis. With the design that we implemented using NI LabVIEW, all the parameters of metering, energy, demand and power quality can be viewed altogether without having the necessity to physically press the button on the power meter one by one to search for the value of the parameter that we are looking for. To sum up everything, our system makes the monitoring on power meter easier using NI LabVIEW through the communication protocol of Modbus. In addition, it is extremely useful and important to record and keep track on the data and parameter viewed. Thus, the logging functionality is added into the system whereby the user can view the saved file in the near future. The setting up of the Power Meter monitoring and logging system using Modbus is shown in Figure 1.
There are many types of power meter available in the market. All the basic features needed to monitor an electrical circuit is offered by Power Logic PM1200 multifunction power meter. It measures basic measurement, energy, power, demand, THD and many others which all of this measurements can be monitored in NI LabVIEW simultaneously, recorded and saved into files. Furthermore, energy and power monitoring, load studies and circuit optimization, energy balancing and optimization can be done by using the system implemented using NI through the communication protocol of Modbus.
Modbus is a serial communication protocol that allows the devices with Modbus capability to communicate to each other. It is one of the commonly used protocols used in the industrial environment because it is easy to deploy and maintain in addition to that it is openly published and royalty-free. Modbus enables approximately 240 slave devices to communicate with the master device connected to the same network. In order for the communication to take place, a USB-to-RS485 module is used as seen in Figure 1. Each device intended to communicate using Modbus is given a unique address which can be edited anytime by the user in the setting menu. A Modbus command contains the Modbus address of the device that is intended to communicate. Only the device with the address will respond to the command although all the connected devices is receiving the command.
NI LabVIEW provides a user-friendly platform for the user to monitor and record the measurement, energy, power, demand, and THD on an electrical circuit which may be a single phase motor or any other load. Firstly, the power meter with Modbus communication capability is connected to the PC by using a USB-RS485 module which enables the serial communication between these two devices. The power meter act as the slave device with a specific slave address assigned to it, which in this case, slave address of 1 is assigned. On the other hand, the PC act as the master device that constantly monitors the changes in the measurement. This is where the NI LabVIEW came in handy. The Modbus Library is downloaded from the NI’s official website. This library file has eased the interfacing between the PC and the Power Meter. Other Power Meter can be used in this system. However, the register’s address might be different and thus the initialization needs to be done before running the program.
In this system that works with PowerLogic PM 1200, the starting register is set to be 3911 and total of 90 registers are read and the significant measurements are displayed on the system. These measurements are categorized in the front panel: Metering, Energy, and Demand in order to ease the monitoring process as demonstrated in Figure 2. The measurements can be viewed in term of a chart as shown in Figure 3. Whenever the measurements are displayed on the chart, it is recorded and saved into a file which could be a Microsoft Excel (.xls) or Text (.txt) file. The date and time are recorded into the saved file at the same time so that it can be used as the reference in the future.
The use of NI LabVIEW enables a monitoring interface to be developed easily for the Power Meter. LabVIEW software has the VISA driver which is able to access any computer for serial communication, thus greatly simplifying the process of developing the communication program for the system. In addition, programmers are able to freely design a control interface as one wish. Besides monitoring this particular power meter’s measurement, the LabVIEW program can be set to interface with other power meter or any device with Modbus communication capability which is also made possible by LabVIEW’s VISA.
NI LabVIEW provides a perfectly reliable stand-alone platform to implement power meter monitoring and logging system. The implementation of this system is easier to take place by using NI LabVIEW to build the virtual instrument and perform an effective graphical system design approach. This, in turn, provides more opportunities for more researchers to program and implement their design since NI LabVIEW is a lot more user-friendly than the other conventional way of programming. Thus eliminating the challenges faced by modern academic research and development.
NI LabVIEW provides a powerful platform to develop and test the system at a considerable low cost which is an advantage for all the researchers. Also, NI LabVIEW symbolizes a more efficient and effective way to implement in educational training for designing better systems since NI LabVIEW is compatible with other non-NI products which make NI LabVIEW a better choice for programming.
NI LabVIEW software is a convenient and versatile tool for monitoring and logging. The software is not limited to the control of a single power meter. Up to 240 slaves with Modbus-enabled capability can be connected to the PC and all their measurements and readings can be viewed through NI LabVIEW. On top of everything, the program itself is easy to be developed and modified, hence, proving that NI LabVIEW software is highly suitable for monitoring and logging applications.