Some controllers have an Inhibit Phases feature. It prevents a phase from turning green when another phase is green.
Let's assime that if phase 1 follows phase 2, yellow trap occurs. So phase 1 must be inhibited if phase 2 is on.A. Some controllers require a diode connected with:
the - end connected to Phase inhibit of the phase to be
inhibited (phase 1).
the + end connected to Phase On of the phase that is to
inhibit a phase (phase 2).
B. Other controllers have settings to inhibit phases when other phases are green:
-- Inhibit ph 1111111
ph| 12345678 90123456
1 | ........ ........
2 | X....... ........
3 | ........ ........
4 | ........ ........
5 | ........ ........
6 | ........ ........
7 | ........ ........
8 | ........ ........
This shows inhibiting phase 1 if phase 2 is on.
I wrote this page when the one I had linked to disappeared.