SCADA PLCs are flexible because they can be programmed. Unfortunately, this does mean that you'll have to spend a lot of time programming them.
In some setups, you'll be designing logic chains to be carried out when certain "trigger events" occur. This is common in manufacturing.
RTUs are smarter than PLCs and have higher capacity, but they perform the same "remote" function. They're also out on the front lines of your operation. Because they're smarter, however, they don't require programming.
An RTU web interface is a great example of "configuring" a SCADA implementation rather than "programming". After you've wired some inputs into the RTU, you'll have to tell the RTU (via its web interface) what to call each item. Did you wire in a temperature sensor? A generator voltage? Something else?
Higher up the chain, you'll need to perform similar programming of your master station (HMI). This is important, because your master station brings together all of your RTU/PLC elements into a single view. "Programming" in a master/HMI context involves creating maps or diagrams that provide a view of your system in an emergency. You want to see exactly WHERE a problem is, not some code number or label.
One client came to DPS with the following requirements:
A basic solution for this scenario would include:
The T/Mon master station and NetGuardian RTUs would need to be configured/provisioned (much easier than "programming") in their own interfaces to complete this SCADA installation.
SCADA technology is a more modern version of network alarm monitoring tech that's been used since the 60's. The broader term defining those systems is "DCS" (Distributed Control System). Factories are big users of these systems.
The trouble with DCS, however, was that it wasn't meant to cover a large area. Think "single plant" rather than "gas distribution network".
SCADA, on the other hand, was built to meet the need of large area usage (or even an entire nation).This opened up new doors and remote-management options in several industries, including: manufacturing, water and sewage, electric power generation and mass transit.For this reason, SCADA programming is a very important skill in the modern economy.
Real-world conditions must be switched to machine language and then into signals that humans can read, record, and analyze. Therefore, SCADA system development involves programming at various levels. In SCADA programming, data is collected at the Remote Telemetry Unit (RTU) and has to be changed into signals, which is followed by reading this data that requires a Human Machine Interface (HMI). Often, this data also has to be grouped and stored (history databases) for trend and analysis work. As a result, unique database systems have to be developed. Networks and communication systems bring in more varied requirements.
How exactly you'll do your programming depends on the system. In some setups, you'll be designing logic chains to be carried out when certain "trigger events" occur. This is common in manufacturing. If you work with a large-scale network (telco, power utility, railway, government, etc.), it's more likely that you'll be working in simpler interfaces and won't really be "programming" in the traditional sense. You won't be writing code on a dark terminal somewhere.
While SCADA technology was developed somewhat later, similar monitoring systems have been in use since the 1960s. Such systems are called DCS (Distributed Control System). DCS have been used for facilities like factories.
However, such systems are not effective in covering large areas like those used in gas transport systems.
SCADA has been specifically developed to meet requirements covering large territories. Therefore, such a system can be used in various industries and for industrial processes. This includes: manufacturing, water and sewage, electric power generation and mass transit. This is why SCADA programming plays such a big role in the system's development.
It can also be used for facility processes in private or public facilities. This includes: buildings, airports, ships, or space stations. This is done to monitor and control: HVAC, access control, and energy use management. The possibilities are endless.
Data collection begins at the PLC level and includes readings and gear statuses that are communicated to a master when needed. Data is then compiled and formatted in such a way that a control room operator using an interface terminal can make supervisory decisions that may be required to adjust or override normal PLC controls. The tags (data) are collected locally in the SCADA software database or into a Historian (distributed database) to allow trending and other analytical work. SCADA programming by a technician adjusts the system as needed.
These dispersed measurement and control systems provide manufacturers with a flexible software solution that can be tailored to meet their exact manufacturing needs.
RTUs and PLCs today are capable of controlling the actions within their range of vision through closed loop feedback systems. The central station oversees the overall performance of the one or more RTUs/ PLCs under its control. SCADA systems also allow staff or supervisors to change the settings as appropriate at the level of the RTU or the central station. Alarming conditions like high temperature can then be stored and displayed.