Possible SPAD
The Possible SPAD alert is designed to fire when a signal appears to be passed whilst at danger. This will often fire in the event of a signal reversion, which could be caused by various conditions (e.g. Track Flick).
The alert is deliberately named "Possible SPAD" as it should be used to indicate a possible fault in the signalling system rather than a driver fault.
Real Example
(The train occupying AB track circuit enters AC track circuit while 101 signal is at danger)
Input Channels
Berth Track Circuit TPR | Digital input channel for the berth track circuit (TPR immediately before signal) |
---|---|
First Track Circuit TPR | Digital input channel for the first track circuit (TPR immediately after signal) |
Signal RGK | Digital input channel representing the red (danger) state for the signal |
Logic
The alert will fire when the First TPR goes occupied whilst the Berth TPR is occupied and the Signal RGK is at danger.
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This alert will not currently work for some junction layouts.
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