CAREL has widened its range of I/O expansions with the development of a new digital input expansion board, the pCOe Digital Input.
I/O expansions are modules that can be added to a typical air conditioning application to increase the number of inputs and outputs available on the controller and consequently optimise the flexibility and modularity of the solutions.
According to CAREL, one of the most common uses involves ventilation sections comprising several fans with electronic motors; in this case, the speed of the individual devices needs to be monitored in order to check their operating status and act on the other fans accordingly if one of them fails.
CAREL already offered tools to support large systems, such as air handling units or dry coolers, in which the fans are equipped with electronics that communicate via Modbus, making it possible to directly monitor their operating status. But these tools were not suitable for smaller units with simpler and more economical fans that do not feature serial communication and provide a pulse signal based on the rotation speed, which can be read by fast digital inputs.
To address this, CAREL has developed a new digital inputs expansion board, which it describes as “an ideal solution for all cases where numerous digital inputs (including fast inputs up to 500Hz) need to be read, however while limiting the total number of I/Os and space required, adding only those that are needed”.
CAREL says that one typical example involves so-called “in row units” used for cooling data centres, highly compact units that do not require complex device control architecture or specific sensors for their operation. These feature a single ventilation section with at least eight fans in parallel, which need to be monitored individually. In this case, reading the signal is a simple and effective way to verify operation, as well as being a more economical solution than installing expensive air flow-rate sensors.
“The new expansion board features a high number of digital inputs to ensure maximum flexibility in different applications,” says CAREL. “This is essential on units where the main controller features a limited number of inputs and outputs, while multiple digital inputs need to be connected, for example to detect alarms or various signals.”
According to CAREL, the range of I/O expansions can be integrated into solutions based on the CAREL pCO and c.pCO programmable controller platforms, or into architecture using different controllers.