Basic design concepts – Distributed process control
You will often split large plants into distinct physical sections. Therefore, you can shut down one part of the plant for service and repair, and it will not affect other parts of the plant. VIGO6 supports this idea. To clarify, you can divide your related control systems to match the physical sections. This means, that you don’t have to write your control logic from the start to end. You just pick the physical parts that you need for your plant. Examples are – valves, pumps, and PH probes. Afterward, you can design the control logic to make the parts work, both alone and as a whole.
Basic design concepts – Control component – tying mechanics and views together
In VIGO6, you build your control system with control components that you program in COPP – short for Component Oriented Process Programming. You design control components to direct physical parts. Afterward, you can create views for them.
PROCES-DATA has designed a large number of control components with views. When you inherit from one of them, the new type inherits both control logic and views. You can run them in manual and automatic mode.
Basic design concepts – Reusability for input control
Figure 1 shows an example of a control component that connects to a field device. It is a digital input that detects logical inputs. Also, the design is broad, which means that you can use it for many things. The views for it include:
Basic design concepts – Reusability for output control
Figure 2 shows an example of an I/O control component that connects to a field device. It is a broad control of digital output. It can turn on outputs as a solenoid valve, relay, or a lamp.
The views are the same as for the input.
Basic design concepts – Building complex control components
Now let us build a control component for an air operated process valve.
The needs for the control logic are:
- The process valve opens when a solenoid air valve activates.
- It has a micro switch that shows the process valve is open.
- It has a micro switch that shows the process valve is closed.
- You can operate the process valve manually or automatically.
When we inherit from the control, our valve-control includes manual and automatic mode. As a result, we limit the process control to the control of the output and check of the two inputs.
The valve control needs access to output and two inputs (the ones we showed already). To gain access, you add connectors to two inputs and one output. Figure 3 shows the process.
Once the needs for the physical input or output device change, you only have to adjust the code for the given component. As a result, the plant can keep running, and use the new input devices. You do not have to change the entire plant logic.
Basic design concepts – Adding control components in assemblies
A valve assembly has a number of physical parts along with their connections. In the same way, the valve control assembly has four premade control components:
- One output
- Two inputs
- The valve control logic
- Their connections
Basic design concepts – Views in views
You can create a view for the control assembly, where you can add the view for the valve. This view can link to premade views for components for the input, output, as well as the valve control. Figure 4 shows a basic idea of VIGO6. You can add instances of premade components in an assembly, to make new control functions. Views of a new control can link to views created for the instances.
When you use premade and tested control functions with views, you can:
- Reduce time spent on programming and testing.
- Ensure faster commissioning.
- Ensure a conform visual look for the operator.
Basic design concepts – Use assemblies to build a plant
We can use our valve control assembly, along with the other types we have used earlier as building blocks for more complex setups. In the example in figure 5, we build control for a pump station. We write the control code that manages one valve, three pumps, and a pressure gauge.
When we have designed one pump station, it is easy to use it in a greater system. We can design a system with two of the same stations on two different sites. In the example on figure 6, there is no physical connection between the stations. As a result, you don’t need more control logic.