Radiocrafts’ Solution For Wireless Sub-Metering Networks – RIIM

The Sub-GHz mesh module, RIIM, is an easy-to-use wireless communication network completely embedded within an RF module. The module includes all the essential components required to design a complete wireless sub-metering network. This means that you do not have any additional upfront costs such as subscriptions or license fees. Furthermore, since RIIM is a mesh network, it is self-forming, self-healing, and self-optimizing. This plug-and-play process simplifies the commissioning of your sub-metering network greatly because the whole process is fully automatic.

In addition, Modbus RTU wireless sub-meter monitoring is very easy to implement out-of-the-box with RIIM using our example code on GitHub.

Modbus is frequently used for interfacing with sub-meters. That being said, RIIM supports quick Modbus integration based on readily available example code as mentioned above. Find more information in our application note below as well. 

Superior Performance In Concrete Buildings and Steel Structures

Sub-GHz mesh radios such as RIIM are well suited for penetrating building materials and therefore, offer long range to reach even the farthest sub-meter in your building complex and highly reliable data transmission success rates including in challenging indoor environments where there are walls and floors made of reinforced concrete and interference from other radio solutions.

In addition, RIIM uses a frequency hopping mode in the PHY/MAC Layer called TSCH (Time-Synchronised Channel Hopping) which works by sending data packets at various frequencies and at different time slots in a synchronised schedule. If a packet is lost between two sub-meters, it will be re-sent on a different channel in the next available time slot.

Therefore, TSCH gives you the power to create a wireless sub-metering network with plenty of safe margin, including in environments with concrete obstacles and significant interference, creating a highly scalable mesh network with minimal packet loss and unmatched reliability.

TSCH has a proven track record of 99.99% successful data packet delivery rates.

RIIM also takes advantage of a ground-breaking technique called Polite Spectrum Access which adds even more reliability to your system. Polite Access Spectrum uses a combination of two features, Listen-Before-Talk (LBT) and Adaptive Frequency Agility (AFA).

Listen-Before-Talk is a technique where the radio scans the channel assigned it by the TSCH frequency hopping list before transmitting data on it. From there, if the channel is found to be noisy, the radio waits and does not transmit which dramatically increases the radio’s resilience to noise.

Adaptive Frequency Agility works by scanning and marking all channels which are often found to be noisy and drops them from the TSCH frequency hopping list. This ensures that the radio only transmits data packets using the best and least noisy channels.

Combining the Polite Access Spectrum techniques with Time Synchronised Channel Hopping and Sub-GHz mesh radio allows you to create a massively scalable wireless sub-metering network to cover an entire building complex or series of buildings with unmatched reliability in a single network. 

Read more about Polite Spectrum Access, TSCH, and Reliability in RIIM below!

Robust 2-way Communication For Both Consumption Reporting And Control of Smart Grid Architecture

Radiocrafts’ RIIM Sub-GHz mesh radio supports symmetrical 2-way communication meaning the downlink data communication is as efficient as the uplink communication. This means that you can send consumption reporting data from the sub-meter up to the gateway just as efficiently as you can send control messages and firmware over-the-air updates down from the gateway to the sub-meters. Fr example, RIIM can achieve firmware over-the-air updates for the entire wireless sub-metering network in under 3 minutes which is exceptionally fast compared to other Sub-GHz mesh technologies.

A large difference from the sub-metering segment compared to the traditional one-way consumption reporting from the smart metering segment is the control aspect. A wireless sub-metering network needs to monitor electricity, gas, water, and heat in a much more fine-grained level than with traditional utility metering which raises the requirement for a control aspect as well. The control aspect arises from a more complex generation and consumption architecture encompassing peak-saving, EV charging, distributed energy storage, energy generation (ex: solar), and a continuous exchange of price signals to match consumption with generation. This complex architecture shows a clear need for a robust and efficient 2-way communication solution such as RIIM.

High Data Throughput and Low Latency For Feed-in Control And Frequent Looping

For feed-in installations the sub-meter must be polled at a high rate in a control loop. In these situations you need to guarantee enough data capacity for  the sub-meter communication in a reliable manner. This is where RIIM shines once again with the Polite Spectrum Access technique.

In addition to giving higher reliability, Polite Spectrum Access also ensures that radios use the available spectrum space politely, thus, allowing the radio to exceed the 1% duty cycle restriction in Europe. According to ETSI regulations, a radio implementing the Polite Spectrum Access technique can increase the on-air time on a single channel from 1% to 2.76%, multiplied by 14 channels implemented in Europe. This means that your wireless sub-metering network’s duty is now roughly 37%. In other words, you can send up to 37 times more data. To illustrate using an example, you can now go from 1 data packet reaching the gateway every 4 seconds to 37 packets every 4 seconds!

This technique is a game-changer for applications such as sub-metering that have high data capacity requirements and need to be polled several times a second. It also ensures that your control loop operates within grid code regulations with less time sensitive communication in the system. This is all possible with RIIM, including a 150 kbps mode to ensure all data capacity requirements are met.

ModBus Integration out-of-the-box – DIN Rail Device

In Sub-metering applications there is a widespread use of wired busses like Modbus running over wired interfaces like RS485. In many cases, wireless is a strong option to wired interfaces. Specifically in retrofitting existing sites, where cable is extremely costly. The return on investment is much better for wireless. Radiocrafts’ RIIM module out-of-the-box supports transferring ModBus over wireless.

For this reason, Radiocrafts has also designed a DIN Rail device which simplifies your installation and lowers cabling costs significantly. What does the DIN Rail device offer your wireless sub-metering network?

• It extends Modbus RTU with Sub 1-GHz long range wireless communication over RIIM
• Long range (Outdoor up to 6 km LOS, indoor typically up to 150 meter)
• DIN Rail housing for easy installation
• Can be connected to both Modbus client and Modbus server (Master/Slave)
• Can support up to 32 servers (slaves)
• Customizable

The DIN Rail device offers several benefits to your system including:

• Installation and commissioning in minutes
• Removes hours of cable installations
• Ultra-reliable and low latency communication
• Customizable
• Supports over-the-air (OTA) firmware upgrades
• and more!

RIIM Support Tools