What do I do if the whole RS-485 BUS network goes down?

This is usually due to a RS-485 Collision issue – a node is remaining in transmission state.

To fix this issue follow these steps:

1. Measure the RS-485 Input/Output to common (S) (should be around 2.5Vdc each leg) for all units.
2. Isolate each panel from the BUS before measuring.
3. Once you determine the faulty panel, upgrade the firmware to the panel.
4. Use direct USB connection to the panel for firmware upgrade after recycling the power.
5. Then put the panel back online.
6. Ensure that the panel is properly grounded.