Honeywell Analytics
Fire Sentry Corporation
6349-001
Revision 1.2, Release Date: 15 February 2013
Page 13 of 16
12.3
Self-Test
The FS24X executes a self-test sequence every three seconds. All optical sensor channels
and the related processing of sensor data are evaluated to ensure that analog circuits,
processors, and memory are functional. Depending on the particular function, tests are
repeated a number of times to confirm device status prior to declaring a fault. In the case of
the optical self-test, which evaluates the optical system by flashing an IR LED and
monitoring the reflection from the housing grill, a fault in not declared until a total of 180
consecutive test attempts have failed. This takes a total of nine minutes to complete.
Additional self-tests are conducted on a continuing basis to ensure the continuity of relay
coils.
Following power-up or reset, the analog output is set to 4.0mA and the device will not
respond to HART® commands. During self-test, the analog output is held at its last value,
and the device may respond normally to HART® commands. Continuous self-testing is part
of the normal device operation.
12.4
Command Response Times
Approximate command response times are listed in the following table:
Minimum
20ms
Typical
50ms
Maximum
100ms
