SCADA is a generic legacy term that stands for “supervisory control and data acquisition.” This type of data communication system automatically gathers pertinent information and uses it to monitor and control processes. SCADA systems are most frequently wired through programmable logic controller (PLC) wireline and often used in critical industrial applications like detecting water leaks in data centers.
However, adding wireless to SCADA is relatively new—and is most often used to get data out of a closed-loop system. Below are two methods for transitioning to wireless SCADA, a review of SCADA vs. IoT, and a few wireless technology SCADA options you can use.
Transitioning To Wireless SCADA: Two Methods
1. Adding wireless data acquisition to an existing SCADA network.
Wireless technology can be used to tap into an existing SCADA network and pull data out (or push data in tactically—without disturbing the existing operation of a MODBUS or ProfiBUS-type system). Let’s say there is a SCADA system monitoring the pressure on an oil well, and the data gathered about that pressure talks directly to a PLC that drives the cycle rate of the oil pump. As the pressure drop decreases, the cycle rate increases.
If you wanted to monitor this cycle wirelessly—say, to determine how fast the pump was going or the rate at which it was running—you could add a wireless tap to the existing BUS and extract data from that point. This would require a protocol conversion to process the data before it was sent wirelessly, so the PLC could “talk” to the internet.
2. Creating a new wireless SCADA sensor.
Not everything you may want to monitor is connected via BUS. For example, you may want to put a new pressure sensor on an oil well that is not physically linked to the PLC. That sensor could send the raw pressure data wirelessly over the air to another system, and that system could make a decision before sending it back to the sensor.
SCADA Vs. IoT
It’s important to note that most people implementing a SCADA system don’t think of it as that—they likely think of it as Internet of Things (IoT) or machine-to-machine (M2M) communication.
The primary difference between SCADA and the IoT is that with traditional wireline SCADA, the internet is not in the loop. In other words, the PLC is where the decision is made. In IoT, data has to flow up via the internet to a cloud-based server before a decision is made and the control signal goes back down over the internet to the sensor. That IoT architecture is less robust than traditional SCADA because the internet is required—and the internet is not foolproof. (There’s a reason nuclear power plants aren’t controlled by the IoT!)
Wireless SCADA Technology Options
Cellular is the gold standard for wireless SCADA if you can afford to pay the cellular bill for every sensor, and if you have good network coverage. You can read more in our Definitive Guide to Cellular SCADA.
2. Symphony Link
Symphony Link is a carrier-grade wireless connectivity solution that is excellent for SCADA. It works better in situations where you have either a lot of endpoints or an area where there is no cellular coverage. Here are a few considerations:
- If you set it up right, you can achieve 20-40 miles of range.
- Each Symphony Link gateway supports thousands of endpoints.
- The Symphony gateway can backhaul via satellite or cellular for more sophisticated remote monitoring and control processes.