How to Troubleshoot the Multiplex Bus Troubles on DS7400 Series

Issue

Multiplex troubles and loss of communication to devices.

Solution

Perform the Following Troubleshooting steps

1. Check the voltage on the Mutilplex Bus
2. If the Voltage is 12VDC

3. Check and make sure the panel is out of programmer’s mode
4. Look for duplicate addresses
5. *Disable Bus lock
6. Make sure 12VDC is not connect to the Multiplex bus

If the Voltage is 0 - . 3VDC
1. Check for Shorts on the multiplex loop
2. Check for reverse polarity to devices
3. If the device require diodes make sure the cathode side is on the positive side.

* To Disable Bus Lock

1. Enter in to Programmers Mode by code + #0
2. Type in 9999 *5

Part numbers DS7400X, DS7400, DS7400Xi, DS7400XIVER2, DS7400XIVER3+, DS7400XIVER4+, DS7430, DS7436