第七章 Cbus总线说明.pdfVIP

Cbus Cbus Honeywell Honeywell Excel 5000 Excel5000 SymmetrEEBI Cbus 29 Excel5000 Excel 10 Cbus 9.6Kb 76.8KbCbus daisy-chain 1200mC-bus 76.8K 1200m Cbus C-bus Excel5000 Excel 5000 Excel 800 Excel 50 Excel Smart 500 : Switch Setting Baud Rate Up Up to 9.6Kbaud Middle Up to 76.8Kbaud (middle of bus) Down Up to 76.8Kbaud (beginning or end of bus) Honeywell_ C-Bus Up to 30 Excel controllers can be connected to one another via a System Bus (C-Bus). Other C-Bus compatible components can be substituted for any of the 30 Excel controllers. Examples of C-Bus compatible components are XM100 modem device, the Excel Zone Manager, and Excel Building Supervisors. The C- Bus allows controllers and devices to exchange data such as measured values, alarms log, and trends. This means that values from one controller or device can be sent to the entire system. Besides allowing communication between controllers and devices, the C-Bus also enables the entire system to be connected to PC centrals. When a controller does not have a modem directly connected, the C-Bus also allows controllers to communicate with other controllers that do have a modem connected, so that data can be transmitted via the public telephone network. The C-Bus supports multi-master communication using the token passing procedure. A bus master is a controller governing communication between bus devices. The master asks for data and then distributes the data on the bus. Controllers transmit data only when asked for it by the master or when they assume the function of the master. Multi-master communication means that all controllers in the system can function as the master, so the right to request and transmit data is not permanently assigned to a specific controller. This has the advantage that a part of the system can still continue w