![background image](http://html1.mh-extra.com/html/campbell/0871lh1/0871lh1_instruction-manual_3754707015.webp)
Continuous BIT consists of verifying the following:
•
The probe heater is in the correct state. The return leg of the
heater is monitored.
•
The ICE discrete output is in the correct state. The ICE discrete
output is fed back to the microcontroller through a passive
voltage divider and voltage comparator.
•
The MSO is operating correctly. Frequencies between 39000 and
40150 Hz are valid.
•
The probe heater is de-icing correctly. After turn-on, the probe
heater must cause the MSO frequency to return to at least 39970
Hz within the 25 second timeout or it is considered failed.
•
Probe is de-iced within 25 seconds. (De-Icing Fail).
5
BIT Failure That Disables Ice Output
The Ice output is disabled due to Continuous and Initiated BIT
failures as shown in Table 1. BIT Information. Ice detection is
disabled when these failures occur because the integrity of the ice
detection capability has been compromised.
13