DMC worked with the client to program and commission 13 POINT IO modules and 16 Turck IO blocks, along with several VFDs that all feed back into one Allen Bradly Control Logix 5580 PLC. Connecting each remote IO module to the PLC via ethernet enables DMC to start the commissioning process as soon as the first remote IO blocks are installed and significantly decreases the time the project would take, as DMC works in parallel with electricians during the construction process. Using only one PLC also proved a central point of communication both for downloading changes to the code and for SCADA integration using Ignition.
The system has several separate zones, many of which are nearly identical. Within the PLC, each zone was given an independent program that was called by a continuous main task. Giving each zone independent programs not only allowed DMC to copy large sections of identical code between zones but also reduced the number of IO points in each zone to a manageable number of points relevant only to that zone’s IO.
Some of the IO locations are in humid environments or places where water might splash on panels; some of the remote IO modules required a higher IP (ingress protection) rating. Using Turck remote IO blocks equipped with M12 connectors allowed for this while still providing a full range of diagnostic information back to the Allen Bradly PLC. In other locations, Allen Bradly POINT IO modules were selected for their wide range of IO capabilities and ease of expansion. This choice proved invaluable as some zones as new IO was added to accommodate new actuators and sensors.
Overall, the system combined Allen Bradly POINT IO, Turck remote IO modules, an Allen Bradly Control Logix 5580 Controller, and Ignition, all to provide one seamless and flexible system. The uses of Remote IO can significantly help increase the reliability and flexibility of a system. Increased flexibility and reliability enables customers to have greater confidence in their system’s accuracy while planning for successful expansion in the future.
DMC has continued working with this client on the development and commissioning of their HVAC control system to regulate building temperature and humidity.
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