Question :
What happens if there is a bad input on the backup side and the primary then fails on an ECO422/D?
Answer :
The behavioral logic of the ECO422D is described in table 2-3 on page 2-8 of the ECO422D user manual (also shown below). One general rule of thumb is that the unit will NEVER automatically switch to a bad signal; it can only switch to a bad signal if told to do so by the user.
As shown on line 1 of the table below, if the backup is bad and the primary fails in normal operation mode then no switch will take place and the unit will remain passing through the primary signals.
| Ln. # | Power | User Config Mode | Switch Button | Primary is… | Backup is… | Output (auto mode) | Output (manual mode) |
| 1 | On | Normal | No Switch | Bad | Bad | No Switch | No Switch |
| 2 | On | Normal | No Switch | Bad | Good | Backup | No Switch |
| 3 | On | Normal | No Switch | Good | Bad | Primary | No Switch |
| 4 | On | Normal | No Switch | Good | Good | No Switch | No Switch |
| 5 | On | Normal | Switch | Bad | Bad | Switch | Switch |
| 6 | On | Normal | Switch | Bad | Good | Backup | Backup |
| 7 | On | Normal | Switch | Good | Bad | Primary | Primary |
| 8 | On | Normal | Switch | Good | Good | Switch | Switch |
| 9 | On | Override | No Switch | Bad | Bad | No Switch | No Switch |
| 10 | On | Override | No Switch | Bad | Good | Backup | No Switch |
| 11 | On | Override | No Switch | Good | Bad | Primary | No Switch |
| 12 | On | Override | No Switch | Good | Good | No Switch | No Switch |
| 13 | On | Override | Switch | Bad | Bad | Switch | Switch |
| 14 | On | Override | Switch | Bad | Good | Backup | Switch |
| 15 | On | Override | Switch | Good | Bad | Primary | Switch |
| 16 | On | Override | Switch | Good | Good | Switch | Switch |
| 17 | Off | n/a | n/a | n/a | n/a | Primary | Primary |
This FAQ Applies to:
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Product:
FAQ ID 64086
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