CAN and the Climate Control Network

Today’s climate control system is a member of the Controller Area Network or CAN. CAN is a standard protocol or set of rules control modules called nodes use to communicate and pass information along a shared line, a line where all modules receive all messages. This system uses smart sensors and actuators that contain microchips and logic. A smart sensor broadcasts its signal to all control modules. Only modules that require this information retrieve it as it passes by, other modules just ignore the message only accepting those necessary for its operation.

AC Class B climate control network.

CAN is segmented into three classes according to speed. Class A is slowest up to 10 Kbps. Class B operates at speeds up to 125 Kbps and Class C up to 1 Mbps. The climate control system operates on a Class B network. The actuators are usually segmented into a LAN Local Area Network like the one in the illustration. Each actuator contains a chip with a unique ID that is capable of receiving position information from the control module, but also capable of indicating its actual position back to the controller. This is because CAN provides bidirectional communication. One of many benefits provided by the CAN networking protocol. Another important benefit has been the reduction in harness size. This is because modules, actuators and sensors share the same line.