Product Guide
VESDA ECO Detector by Xtralis
30
Principles of Operation
17898_05
Alarms
The ECO detector will generate Alarm conditions when the associated gas reading
exceeds the configured threshold(s). These alarm conditions are used to switch the
state of both the Relays AND the status indicators (see page 25).
Alarm Threshold Configuration
The default alarm thresholds in the ECO detector are set during manufacture
dependent on the Gas sensor configuration (refer to Appendix A – Gas Types,
Ranges & Defaults on page 82 for details).
If necessary the alarm thresholds can be changed using the VSC configuration tool
(see page 50 for instructions).
Alarms may be configured as “Latching” or “Non-Latching”.
•
“Non-Latching” - the indicated alarm condition will be de-activated as soon
as the reading falls below the configured alarm threshold.
•
“Latching” – the indicated alarm condition will remain active even after the
reading falls below the configured alarm threshold, and will do so until an
Alarm Reset condition is generated (see below).
By default, the Alarms are configured as Non-Latching.
Alarm Reset
When an Alarm condition is latched, it may be cleared in one of two ways.
•
Using the digital input connection (refer to page 23 for details), which when
connected to the negative supply input for between 5 and 6 seconds, by
means of a switch, will clear all active alarms.
•
or by using one of the communications interfaces, such as
Xtralis
VSC,
Xtralis
VSM4 or a 3
rd
party monitoring system attached via the USB
connection or RS485 bus interface.
If the condition which initiated the Alarm is still present when the alarm is reset, the
Alarm condition will be immediately re-activated.
Configuration storage
The ECO unit will store new configurations as they are applied, these new
configurations are stored in non-volatile memory within the device and are retained
when power is removed. This memory is located internally, not on the microSD
Card which is where the logged data is stored.
