Can zone 1 be used for burglar on a VISTA 20P?
Although zone 1 on the Vista-20P comes pre-configured from the factory as a fire zone, for use as a 2-wire smoke zone if necessary, it can be changed to any available zone type desired. But, because it can support 2-wire smoke detectors, its characteristics vary from the other 7 hardwired zones available on the panel. Here are some of the differences:
- Zone 1 is isolated from all other zones on the panel. The negative, or low side of zone 1 is not common to any other negative on the alarm panel. All other zones share their negative terminal with another zone, and all are common to each other, and to terminal 4 on the panel.
- Zone 1 must use an EOLR (End of Line Resistor). It does not have the option for NC, or NO only. The tolerance for resistance on Zone 1 is 100 ohms, or put another way, acceptable resistance on Zone 1 is 1900 to 2100 ohms. Tolerance on all other hardwired zones is 300 ohms, or 1700 to 2300 ohms.
- Zone 1 can not be used with Zone Doubling, or Double Balancing.
- When using 2-wire smokes, only Zone 1 can support them, as it is the only zone with available current to power them. By contrast, when using 4-wire smokes, only zones 2 - 8 can be used. This is because when zone 1 is programmed as a fire zone, the panel assumes 2-wire smokes are in use, and that the panel will automatically drop power to reset the zone after a fire alarm. This won’t work to reset a 4-wire smoke. 4-wire smokes are powered from auxiliary power (usually terminals 4 and 5) and need to have power dropped for several seconds to reset after an alarm. There is specific output programming, for use with relays, or panel triggers, that can be used to reset 4-wire smokes, but the logic for those outputs will not kick in for a fire alarm on Zone 1, because the panel assumes a fire on zone 1 will be reset by the zone.
So, in summary, Zone 1 can be used for any zone type available on the panel, however, because Zone 1 is physically different from all other available zones, if used as a fire zone, it must be with 2-wire smoke detectors, never 4-wire, it is more easily faulted because of the lower resistance tolerance, and it must employ a 2K EOLR.
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- Answered By
- Julia Ross