The Definitive Guide to Cellular SCADA and Cellular Telemetry
SCADA (Supervisory Control and Data Acquisition) data communications systems are wireless or wired control systems generally for critical industrial applications. Examples include flow monitoring at a municipal water plant, remote interconnects for smart grid control, or even leak detection systems. SCADA goes by many names, including M2M - Machine to Machine, or even IOT - Internet of Things. In many ways, SCADA is the IOT’s grandfather.
A critical part of any SCADA system is “data transport layer” or how data signals get to and from the sensor/controller of interest. This is done several ways, each with pros and cons.
1. Cellular Scada: Using SCADA over cellular or GPRS modem connected to the sensor or actuator system as a way of connecting to the application data system.
2. Private Radio Systems SCADA: In remote areas (oil fields, mines, oil platforms), or when high service reliability or security (nuclear plants) is needed, SCADA systems will be deployed using a private radio system. Link Labs’ Symphony Link system is considered a private radio system hybrid, since it can be operated with cellular data backhaul. Private radio systems make sense when a large coverage area is needed and there are many assets to monitor.
3. Satellite SCADA: In cases where monitoring/control is in remote areas, but assets are fewer, satellite SCADA can be a good alternative. Drawbacks are cost, power consumption, and the requirement that the sky be clearly visible from the radio.
4. MODBUS PLC (
): PLC is using existing power line wires to transmit data using low frequency RF (10 kHz to 450 kHz). This can be 1 way or 2 way transmission, and provide a great way for utilities and others that already own power lines to repurpose that infrastructure to transmit low rate telemetry data. Many smart meters work on PLC buses.
Advantages of Cellular SCADA:
Probably the biggest advantage of Cellular SCADA is it’s nearly ubiquitous coverage. While some industrial sites have poor coverage, they are becoming fewer and fewer. There are many cellular data modem manufacturers and integrators, like Telit or Multitech.
Disadvantages of a cellular system:
Cost and Power. If thousands of points are being monitored and controlled, costs of using cellular backhaul to each endpoint will add up fast! Also, cellular modems are fairly power hungry, so AC power or solar power (think $) is pretty much a requirement. Another concern of many in the SCADA market is security. If data and control signals are passing over a 3rd party network (like Verizon), there is a greater vulnerability that those signals could be intercepted or manipulated. That’s why many SCADA systems today are still “air gapped” from the rest of the Internet, meaning they are completely stand alone systems.
How is cellular SCADA different from cellular telemetry?
In reality, there’s not a ton of consensus on what exactly the difference is, but if there is a difference, it generally is pointing to the distinction between a full blown TCP/IP enabled data pipe right to the SCADA controller, vs. a tiny-bits-of-data-in-and-out implementation that often use point-to-multipoint data aggregators locally before hitting the cellular network.
Point-to-multipoint-networks provide big power and cost savings.
Link Labs’ Symphony Link - LoRa SCADA system- (shameless plug) is a wireless data telemetry system that is often used in combination with cellular to give wide area coverage to low power endpoints, without the high costs of “cellular to the edge.”
We’d love to hear from you if you’re interested in learning more about Link Labs, Symphony Link, or just want to nerd out on SCADA systems in general.