Manual
User Guide: FAAST Fire Alarm Aspiration Sensing Technology® Modbus Protocol Schema 1
11
Rev A0
Sensor Status
The device’s Sensor Status Structure is READ ONLY with the exception of the Smoke Reference Value and mapped directly to a set
of holding registers. The structure in the Firmware is defined as follows:
Address Size
(16-bit
words)
Parameter Name Type Description
40031-32 2 System Time U32 Device Time in UNIX seconds epoch format, use Universal
Time Stamp instead.
33-34 2 ∆ Smoke Reference Value F32 Smoke reference value used to increase noise floor of
detector.
US Standard Units Max: 0.10 (%/ft)
Metric Units Max: 0.328 (%/m)
35 1 ∆ Sensor Action Inputs U16 All bits are self-clearing and will read ‘0’ after bit has been
read and processed
Bit 0: 1 Isolate – Toggles Isolate Mode
Bit1: 1 Disable – Toggles Disable Mode
Bit2: 1 Test – Place the device in Test Mode
Bit3: 1 Silence Sounder (if enabled / equipped)
Note: Sounder Silence is effective for a single alarm or fault
occurrence. If an alarm recurs, another alarm is initiated or
another fault occurs, the sounder will re-energize.
Bit4: Reset Device
Bit5: Reset Airflow Baselines
Current baseline cleared, and device will set a new
baseline. New baseline established within 15 minutes.
Bit6: Clear Event Log Note: Allow this action up to 10
seconds to complete. Erases all Event Log entries
Bit7: Clear Trend Log Note: Allow this action up to 5
seconds to complete. Erases all Trend Log entries
Bit8: Clear Message Log Note: Allow this action up to 5
seconds to complete. Erases all Message Log entries
Bit9-15: Unused
36 ½ Ch 1 Air Temperature S8 Real-time sampled air temperature in Channel 1
37 ½ Ch 1 Air Velocity Change S8 Percentage change from baseline air velocity in Channel 1
38-39 2 Ch 1 Air Velocity Baseline F32 Average velocity during baselining in Channel 1
40-41 2 Ch 1 Air Velocity Daily Min F32 Daily minimum air velocity realized on Channel 1
42-43 2 Ch 1 Air Velocity Daily Max F32 Daily maximum air velocity realized on Channel 1
44 ½ Ch 2 Air Temperature S8 Real-time sampled air temperature in Channel 2
(multichannel device only)
45 ½ Ch 2 Air Velocity Change S8 Percentage change from baseline air velocity in Channel 2
(multichannel device only)
46-47 2 Ch 2 Air Velocity Baseline F32 Average velocity during baselining in Channel 2
(multichannel device only)
48-49 2 Ch 2 Air Velocity Daily Min F32 Daily minimum air velocity realized on Channel 2
(multichannel device only)
50-51 2 Ch 2 Air Velocity Daily Max F32 Daily maximum air velocity realized on Channel 2
(multichannel device only)