PLC Logic is a product provided by Phoenix Contact. This solution provides small IO potential for the Building Automation market. The controller has enhanced functionality- like PID control- and I feel it is worth you knowing about this as it is capable to communicate over Modbus and integrates well with our Niagara controller ILC 2050 BI. This little gem could be used as a HVAC application but also has potential for other applications too.
The controller is programmed using its own software. Once the program is developed, most of the time, your logic rarely changes but the variable information does in fact change. For example changing the speed of a fan- when a condition in the software is met with an input, an output comes on, reading a fan speed but changing a condition based on that speed.
You might think you have a solution already- centralised control is usually kept with a Modbus communication, but what if the connection was broken because someone, or something, broke it? You lose communication with the IO station.
What happens to that control? With the PLC Logic control, even if that same Modbus connection was broken, the control of the HVAC unit would still exist as the PLC Logic would continue to operate, reducing point of failure.
Furthermore, HVAC units are typically installed outside of buildings so, for security, it has no IP connectivity offering greater flexibility and greater security. It can still maintain system application within the system even if the Modbus communication is broken. This makes it a very cost-effective controller.
