Siemens ST750 General Handbook page 42

ST750 G H
ENERAL ANDBOOK
as faulty, the DFM indicator is illuminated and the detector input forced active
(regardless of the setting of the DFM forcing action command 'DFA').
* Note that for the input to be seen inactive at the 200ms processing rate, all ten
20ms samples must have been inactive.
Thereafter, the force is only removed after 5 consecutive tests of the detector have
passed, but the fault log entry remains set and the DFM indicator remains
illuminated, until RFL=1 is entered.
If the maintenance engineer enters RFL=1, the controller will automatically perform
a test. If a kerbside detector which was reported as faulty passes this test, even if
this is the first test that it has passed, the fault log entry for that detector is cleared
and the detector is assumed to be working. This means that when the maintenance
engineer fixes a kerbside detector, they do not have to wait for 5 automatic tests
before they can clear the fault, they just need to enter RFL=1.
667/HB/33750/000 Page 42 Issue 6