Introduction to Industrial Control Systems
How SCADA Works
How SCADA is transmitted
Originally, SCADA was non-network, meaning there was no communication as it was a closed loop between a RTU, a measurement point, and a control point. Over time, the demand to know more increased resulting in the requirement to have remote visibility over the process of monitoring control.
Methods of Transmitting
The advent of network SCADA started in the mid-to-late 1960. Before this time, a lot of the process was very mechanically oriented. The process included a combination of electrical and mechanical functionality where spring loaded reclosers would pop open as heat caused the spring to contract or expand. Beyond 1960 and into the 1970s and 1980s, the process became more network orientated.
Fiber: Today that process is taking yet another step forward. In certain industries, SCADA is predominantly being provided over fiber. Although expensive, fiber is an ideal choice when risk becomes very high. For instance, if there is an outage at transmission, every distribution company will be affected. Therefore, you would make a much greater investment in things such as fiber optics so that you can deliver services like TDM (Time Division Multiplexing), Ethernet, and more.
Dial-Up: Early SCADA was also dial-up, but a large amount of SCADA is still dial-up today. It is a process that is very time-consuming. Now with emerging technologies, including DMR Tier 3, you can make that process much faster and on an investment you’ve already had to make for voice.
LTE: The carrier environment is promoting a carrier type network solution, LTE. However, in a private network environment, there’s neither spectrum nor the ability to develop sites at the scale that you would need to actually build a private LTE. There are very few private LTE networks in the world today, and therefore most organizations who choose LTE will be required to use Public networks they cannot control.
DMR Tier 3: the best time to use DMR Tier 3 for industrial control type solutions is when your organization has a voice requirement, as well as an industrial control solution that provides mission critical, wide area coverage.
P25 and Tetra are other options for this, but DMR Tier 3 requires the fewest sites for the greatest coverage of most of the wireless technologies that are out there.
Comparing Transmission Methods
When it comes to reliability, the following methods are ranked from most reliable to least reliable:
Fiber > DMR Tier 3 > Public LTE > Dial-Up
When it comes to latency speed , the following methods are ranked from fastest to slowest:
Fiber > LTE > DMR Tier 3 > Dial-Up
When it comes to the size of the pipeline, the following methods are ranked from largest to smallest:
Fiber > LTE > Dial-Up > DMR Tier 3
When it comes to size of coverage, the following methods are ranked from the most wide area to the least:
DMR Tier 3 > Public LTE > Fiber
When it comes to cost, the following methods are ranked from (typically) most expensive to least expensive:
Fiber > Private LTE > DMR Tier 3 > Public LTE
In conclusion, if your organization has an absolute voice requirement, then choosing DMR Tier 3 will enable your company to leverage their voice network for industrial control type applications.