i-on Range The System BusPage 27 If you are confident that the control unit has already learned all the devices on the busyou do not have to carry out a bus scan (but it may be a useful check).If you have temporarily removed a bus device you can reconnect it to the bus, providedthat you carry out a bus scan and do not change its bus address. If, as a result of a bus scan, the control unit offers to re-configure the bus (and youaccept) then new devices will be added to the system only if they already have a busaddress. Missing devices will be removed from the system (along with all details of thepartitions they belong to, and any zone information).Note: Exercise great care when deciding whether to accept the control unit’s offer to re-configure the bus. Once the control unit has deleted device information you will needto re-address and re-program those devices and zones if you want to add them tothe bus again. A bus re-configure is not saved until you leave Installer Menu. If the control unit losespower before leaving Installer Menu then the bus re-configure does not take effect.Zone NumberingWhen reporting alarms to an ARC using CID or SIA protocols the control unit reports eachdetector as a zone number. The i-on160EX numbers zones in a continuous range from000 to 159, the i-on30EX zone numbers run from 000 to 029, and the i-on50EX zonenumbers run from 000 to 049. The zone numbers are independent of the physicalconnection points for each detector. The process of assigning zone numbers to detectorconnection points is called “mapping”.Mapping Zones to ExpandersThe control unit assigns blocks of zone numbers to each expander sequentially.1. The connection points on the control unit PCB take zone numbers 000 to 009 (for FSLor 2-wire CCL wiring) or 001 to 005 (for 4-wire CCL wiring).2. Each expander takes a sequential block of zone numbers, running on from the previousexpander. The numbers are ee0 to ee9 (for FSL or 2-wire CCL wiring) or ee1 to ee5 (for4-wire CCL wiring), where “ee” is the two-digit expander number.Figure 7 shows the zone numbers used by the example system in Figure 5.