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A healthy cavity with no faults will display its cavity number on top of a green diamond. If a cavity does have a fault, there will be a three letter fault code displayed on top of a red hexagon. A gray hexagon with the three letter fault code PKD indicates that a cavity is parked (aka it has purposefully been tuned off frequency so that it will not affect the beam).
A purple circle indicates that the fault PV associated with the cavity is disconnected. A cavity with a three letter code (TLC) fault with a yellow triangle in the background indicates a minor fault, whereas a TLC in front of a red hexagon indicates a major fault. The different shapes used for these faults were chosen with the purpose of making the GUI red/green color blind accessible.