The SA bus connects NCEs, SNCs, CGMs, CVMs, CGEs, CVEs, FACs, FECs, and VMAs (equipment controllers) to endpoint devices, such as IOMs, XPMs, network thermostats, network sensors, and Johnson Controls Variable Speed Drives (VSDs).
On an SA bus, an NCE, SNC, CGM, CVM, CGE, CVE, FAC, FEC, or VMA is the bus supervisor. The SA bus is a private MS/TP bus that only supports those devices that can be defined using the Controller Configuration Tool (CCT) programming tool. The bus does not support bus segments (Figure 1). See SA Bus rules and specifications for more information.