STMicroelectronics Designs Wireless Support for ST8500 Chipset in Smart MetersNovember 14, 2019 by Cabe Atwell
The ST8500 PLC chipset allows smart meters to communicate wirelessly through existing power cables or RF waves.
Electronics and semiconductor manufacturer STMicroelectronics has recently announced wireless communication support for the company’s ST8500 PLC (Powerline Communication) chipset, which is widely used in smart meters.
The chipset allows for both RF and PLC communication. Image from STMicroelectronics
The chipset now allows for wireless communication using existing power cables or RF (Radio Frequency) waves, making it easy for equipment makers to implement wireless or PLC into local infrastructure.
In some cases, power lines may have too much noise, or local regulations prevent PLC from being integrated, in which case hardware manufacturers can easily switch over to RF without the need to swap out chips.
In the STMicroelectronics press release, the company explains, “In addition the built-in RF capability lets equipment designers leverage the ST8500’s high feature integration and ease of use in other smart devices such as gas and water smart meters, environmental monitors, lighting controllers, and industrial sensors.”
What Is ST8500?
The ST8500 is a programmable PLC modem SoC that’s capable of running any PLC protocol at a frequency range of up to 500kHz.
ST8500. Image from STMicroelectronics
It comes outfitted with an Arm 32-bit Cortex-M4F core and features PGA with automatic gain control and ADC, DAC with transmission pre-driver, digital transmission level control, and a zero-crossing comparator.
Bridging Communication With Mesh Networking
STMicroelectronics' embedded support for the RF Mesh at the PHY (Physical) layer, as well as the data-link layer (Media Access Control, MAC, and 6LoWPAN) firmware, provides developers with the flexibility of using PLC and wireless mesh networking as a bridge for communication between smart nodes and data collectors.
When compared to point-to-point links, mesh networking provides increased reliability, fault-tolerant connections, and extended communication distances.
Rolling Updates to ST8500
The company states it continuously updates the ST8500 SoC and companion STLD1 line driver to provide increased functionality. In fact, earlier this year, the chip was certified with the current PRIME 1.4 base node and G3-PLC CENELEC B PAN coordinator specifications.
Block diagram of ST8500. Image from STMicroelectronics
Existing protocols were also updated, allowing for wider use in PLC-equipped network nodes. Those certified solutions provide manufacturers with reduced time-to-market approval and deployment for their products in most areas of the world.
STL8500 Chipset in Action
European smart-metering solutions Add Grup is the first company to implement the ST8500 in their new hybrid PLC/wireless products, including the new ADDAX Hybrid smart meters, which the company explains is based on open G3 standards and offers the same MAC level in RF as it does with PLC. This means it provides full G3-PLC interoperability with products from other manufacturers, as well as future devices that use the same standard.
Add Grup has implemented the ST8500 in their hybrid PLC/wireless products. Image from Add Grup
According to Head of Sales and Marketing Ruslan Casico (Add Grup), “With wireless support now fully integrated in the ST8500 firmware, ST’s chipset is the perfect platform to enhance network performance, reliability, capacity, and scalability for our innovative electricity meters. The hybrid PLC/wireless connectivity of these new products has helped us win important metering projects in EMEA, Russia, and Asia.”
STMicroelectronics has also introduced a turnkey development package designed to help developers create G3-PLC nodes for smart-energy, smart-buildings, and smart-city applications, and features the company’s EVALKITST8500-1 evaluation kit based on ST8500 and STLD1 devices.
EVALKITST8500-1. Image from STMicroelectronics
The package offers modular board architecture, which includes an ST8500 full-performance PLC module (with STLD1 line driver), an STM32 microcontroller-based motherboard for system management, and a STEVAL-ISA175V1 9.4 W power supply board based on the company’s VIPER26HD AC/DC converter.
Block diagram of EVALKITST8500-1. Image from STMicroelectronics
STMicroelectronics is also offering a full open-source firmware framework that includes protocol stacks, 6LowPAN adaptation layer for IPv6, and a protocol-engine/real-time engine firmware images. Rounding out the robust kit is an STM32 application example, along with the STSW-SGKITGUI SmartGrid LabTool GUI toolset used to configure and control the EVALKITST8500-1 hardware, run application commands, and apply firmware upgrades.
Pros and Cons of Dual PLC and RF Compatibility
While outfitting the ST8500 SoC with both PLC and RF support is a novel and efficient communications solution, like all technology, it has its advantages and disadvantages.
On the PLC end, the Powerline Communication platform is easy to use, offers low installation and operating costs, and users are not required to register their equipment since RF is not used.
On the other hand, it’s sensitive to noise interference in both the cable and low-quality equipment not adequately shielded.
On the RF-mesh side, the platform is flexible and convenient for transmitting data from difficult to access smart meters. It also reduces operating costs, doesn’t require a hardline connection, and can be adapted for use in a wide range of applications.
With that said, it does have limited frequency access, has to have access points placed close to customers, and needs a power supply to use.
Those examples though, are what makes STMicroelectronics’ ST8500 SoC worth considering for smart meters, as manufacturers can choose what’s best for the local infrastructure without having to change-out hardware to adapt them for different locations.
What are your thoughts on brownfield developments to connectivity? Drop your experiences in the comments below.