The Automatic Monitor Integrity Test feature instructs the Monitor Interrogator to apply signals to the various executive monitor channels on both Monitor 1 and Monitor 2 to verify the ability of the monitors to detect out-of-tolerance conditions. Should either of the two monitors fail to detect an alarm for an out of tolerance parameter, it will be disabled from the monitor voting logic in the LCU and a monitor maintenance alert will be generated. A disabled monitor is considered by the LCU to be in both primary and secondary alarm state.
3.6.9.2.1 Monitor Alarm Limits Integrity Results
Refer to Figure 3-35. This screen displays the results of the last Alarm Limit Integrity Test performed by the associated Monitor. It shows the measurements for the transmitter made in each integrity test, as well as the high and low alarm limits for each measurement.
Figure 3-35 Monitor Alarm Limits Integrity Test Results Screen (Dual Equipment shown)
For each test case, the monitor sets its test generator to the appropriate Low Test or High Test target value then samples the signal for display and comparison against the monitor Low and High Limits. If the monitor finds that the Low Limit Low Test or High Limit High Test does not generate a monitor alarm condition then that parameter is declared in alarm as shown with a red background. If the monitor finds that the Low Limit High Test or High Limit Low Test generates a false monitor alarm condition then that parameter is declared in alert as shown with a yellow background. The following formula are used to determine the integrity test targets based on the monitor lower alarm, nominal, and upper alarm limits:
• Low Limit Low Test: Lower Limit – (Nominal – Lower Limit)/10
• Low Limit High Test: Lower Limit + (Nominal – Lower Limit)/10
• High Limit Low Test: High Limit – (High Limit - Nominal)/10
• High Limit High Test: High Limit + (High Limit - Nominal)/10
When a monitor fails to detect an alarm for an out of tolerance parameter (integrity alarm), it will be disabled from the monitor voting logic in the LCU as indicated by a red background for the Integrity Test Failed row on the RMS >> Data
>> Maintenance Alert/Alarms screen as shown in Section 3.6.7.2.1. When a monitor detects a false alarm condition the Integrity Test Failed indication will be yellow (integrity alert); although a yellow Integrity Test Failed bit could also indicate a parameter on the Interrogator or Transponder page is out of tolerance. A disabled monitor is automatically re-enabled by the RMS following a successful Monitor Integrity cycle.
As an additional integrity check the RMS verifies that the each monitor completes the cycle of integrity tests within a 10 minute period. Failure to complete all tests timely results in an integrity alarm condition that disables the monitor.
When the Monitor Integrity Tests Enabled bit on the RMS >> Configuration >> General screen is disabled (see Section 3.6.7.4.1), the monitor integrity tests will still be performed but the integrity alarm conditions are downgraded to integrity alerts. Thus the monitors will not be disabled for failure to detect out of tolerance parameters.
3.6.9.2.2 Interrogator Test Results
Refer to Figure 3-36. This screen displays the results of the last Interrogator Test performed by the associated Monitor. It shows the measurements made in each test, as well as the expected results for each measurement.
Figure 3-36 Interrogator Test Results Screen (Dual Equipment shown)
For each test case, the monitor samples the signal and tests each parameter. Table 3-7 indicates the limits used by the Monitor to declare a normal condition. If the Monitor finds that the parameter exceeds the tolerance then the parameter is declared in alert and the Monitor x >> Data > > Test Results shows the background in yellow on the parameter that is out of tolerance.
Table 3-7 Interrogator Test Criteria
Parameter Lower Limit Standard Upper Limit
First Pulse Width 3.0 µs 3.5 µs 4.0 µs
First Pulse Rise Time 1.5 µs 2.5 µs 3.0 µs
First Pulse Decay Time 1.5 µs 2.5 µs 3.0 µs
Second Pulse Width 3.0 µs 3.5 µs 4.0 µs
Second Pulse Rise Time 1.5 µs 2.5 µs 3.0 µs
Second pulse Decay Time 1.5 µs 2.5 µs 3.0 µs
Pulse amplitude difference P1 to P2
-0.5 dB
(Positive for P2>P1) 0 dB +0.5 dB
Pulse Spacing X:12µs, Y:36µs -0.2 µs X:12µs, Y:36µs X:12µs, Y:36µs +0.2 µs
Pulse Rate 25 50 (per monitor) 60
Signal Generator Reference -1.0 dB 0 dB +1.0 dB
3.6.9.2.3 Transponder Results
Refer to Figure 3-37. This screen displays the results of the last Transponder Test performed by the associated Monitor.
It shows the measurements made in each test, as well as the expected results for each measurement.
Figure 3-37 Transponder Test Results Screen (Dual Equipment shown)
For each test case, the monitor samples the signal and tests each parameter. Table 3-8 indicates the limits used by the Monitor to declare a normal condition. If the Monitor finds that the parameter exceeds the tolerance then the parameter is declared in alert and the Monitor x >> Data > > Test Results shows the background in yellow on the parameter that is out of tolerance.
Table 3-8 Transponder Test Criteria
Parameter Lower Limit Standard Upper Limit
First Pulse Width 3.0 µs 3.5 µs 4.0 µs
First Pulse Rise Time 1.5 µs 2.5 µs 3.0 µs
First Pulse Decay Time 1.5 µs 2.5 µs 3.0 µs
Second Pulse Width 3.0 µs 3.5 µs 4.0 µs
Second Pulse Rise Time 1.5 µs 2.5 µs 3.0 µs
Second pulse Decay Time 1.5 µs 2.5 µs 3.0 µs
Pulse Amplitude Difference
P1 to P2 -0.5 dB 0 dB +0.5 dB
(Positive for P2>P1)
Ident 1340 Hz 1350 Hz 1360 Hz
Equalization Pulses 90.0 µs 100.0 µs 110.0 µs
Dead Time Gate Established Value -5.0 µs
Established Value (60µs nominal)
Established Value +5.0 µs
3.6.9.2.4 Decoder Results
Refer to Figure 3-38. This screen displays the results of the last Decoder Test performed by the associated Monitor. It shows the measurements made in each test, as well as the expected results for each measurement.
Figure 3-38 Decoder Test Results Screen (Dual Equipment shown)
For each test case, the monitor samples the signal and tests each parameter. Table 3-9 indicates the limits used by the Monitor to declare a normal condition. If the Monitor finds that the parameter exceeds the tolerance then the parameter is declared out of tolerance and the Monitor x >> Data > > Test Results shows the background in yellow on the parameter that is out of tolerance.
Table 3-9 Decoder Test Criteria
Receiver Decoder Parameters Standards Limits
Receiver Sensitivity @12 µs -94 dBm (ref) ± 3 dB
13 µs(X), 37 µs 100% decodes S70%
12.5 µs (X), 36.5 µs (Y) 100% decodes S70%
11.5 µs (X), 35.5 µs (Y) 100% decodes S70%
11 µs(X), 35 µs (Y) 100% decodes S70%
+200 kHz 100% decodes S70%
-200 kHz 100% decodes S70%
+900 kHz 0% decodes X 5%
-900 kHz 0% decodes X 5%
9.0 µs (X), 33.0 (Y) 0% decodes X 5%
10.0 µs (X), 34.0 (Y) 0% decodes X 5%
14.0 µs (X), 38.0 (Y) 0% decodes X 5%
15.0 µs (X), 39.0 (Y) 0% decodes X 5%