Texas Instruments has sponsored the following story
Texas Instruments (TI) has created a development kit to produce a PLC concentrator using the open source BeagleBone Black board .
Power Line Communications Background
One of the most extensively used applications of the PLC technology is in the remote, automatic, reading of consumer power meters. In the “good old days,” the meter reader employees went around the grid territory, reading consumer power meters, recording the information, and then submitting that information to the people responsible for generating the bills. Using bi-directional PLC communications, however, the owners of the power grid can poll the individual power meters, gathering the real-time information, and avoid transcribing the old handwritten data entries. The information is timely, cheaper, and uses an infrastructure the company already owns.
There are two general classes of PLC; narrowband and broadband. The narrowband covers the lower frequency ranges of 3KHz to 500KHz, while the broadband typically operates in the 1.8MHz to 250MHz frequency ranges. The general tradeoffs between the two classes include distance and data rates. In this case, narrowband has lower data rates but can cover longer distances.
There are a variety of standards for PLC narrowband systems, ranging from the IEEE P1901.2, ANSI/EIA 709.1.2, IEC 61334, and G3-PLC. Of particular interest, at this time, is the G3-PLC which covers use in the 36KHz to 90.6KHz frequency range and data bit rates of 5.6Kpbs to 45Kbps.
Texas Instruments has developed a G3-PLC development kit for a Power Line Communications data concentrator on the open source Beaglebone Black platform. The kit, TMDSPLCKITV4-CEN, can be used to form a small network using the PLC modems from the kit. The BeagleBone Black platform is not designed as an end-product component but rather a development tool for designers.
board PLC Data concentrator.
Some of the parts in the PLC Kit includes a number of different interface cables, control units, and a circuit board mounted on the BeagleBone base . TI has also included documentation to help with the implementation of the kit .
The mounted circuit board is the Texas Instruments SOMPLC-F28PLC83 system module. This board supports Power Line Communications including both PRIME and G3 standards. Once completed and released the system should also support the IEEE P1901.2 standard. The circuit board contains a 34 pin header which allows the developer a choice in control and inputs.
While there are a number of standard protocols supported, there is no native RS-232 driver on the SOMPLC card. If RS-232 communications are required by the developer then it will have to be accommodated externally from this system module. While there are a number of communications options available to the developer, there is only one required by the SOMPLC. That requirements is for a serial channel connected to one of the UART ports on the SOMPLC. The standard requirements for the required interface are:
- Baud Rate = 57600
- Message Bits = 8
- Stop Bits = 1
- Parity = None
- Handshake = None
What is the Future of Power Line Communications?
Where can PLC applications go in the future? The answer is “Where can you think to put it?”
For instance, PLC has many green applications from solar panel interfaces, electric grid control, grid problem detection and solution implementation. The application of green PLC control could also enter the home. Refrigerators, water heaters, washers, and other similar large current home devices could be controlled to work hardest during off peak hours. These applications would help the electric supplier better balance the demands on the power system, and could act as saving incentives to the home owner.
Another PLC application being investigated is an adaptation of PLC to DC power lines for automotive applications. For example, in a tractor-trailer, information from the trailer (brake heating, tire pressure, internal temperatures, etc.) could be transmitted to the tractor alerting the driver of specific conditions. This could improve road safety and fuel consumption.
One thing is for sure, with the BeagleBone Black open source community using PLC , we will see some interesting innovations in the future.
Texas Instruments has sponsored promotion of their power line communication kit on ENGINEERING.com. They have no editorial input to this post - all opinions are mine. Ray Floyd