Comfort Automation/ Security System Forums

Hello, i\'ve suddenly experienced a communication failure for slave 1 and then for slave 2.I\'ve already checked and tight all ID jumpers on all slaves and UCMs.From the keyboard i heard \"Communication Error, 34\".See also the screenshot attached.The Comm failure for both slaves and the comm restore continue forever.The green LEDs on both slaves stay on, then flash once, then i hear the Comm failure alarm. Any advice on how to solve this?
Some advices: Slave 2 is connected via the 4 pole cable to the Slave 1. Slave 1 is connected to the main board via the KA KB 2 pole connector. Slave 1 has its own battery and transformer and powers Slave 2 too.

Below, the log:

Code:
03/17 13:58 ....all normal before, then:

03/17 14:13 Comm. failure # Slave 1

03/17 14:13 Comm. failure # Slave 2

03/17 14:13 Alarm Type # RS485Comms (24)

03/17 14:13 Sign in - User # 1

03/17 14:13 Sign in - User # 1

03/17 14:14 Comm. restore # Slave 1

03/17 14:15 Comm. failure # Slave 1

03/17 14:15 Alarm Type # RS485Comms (24)

03/17 14:15 Comm. restore # Slave 1

03/17 14:16 Comm. failure # Slave 1

03/17 14:16 Alarm Type # RS485Comms (24)

03/17 14:23 Comm. restore # Slave 2

03/17 14:23 Comm. failure # Slave 2

03/17 14:23 Alarm Type # RS485Comms (24)

03/17 14:24 Comm. restore # Slave 1

03/17 14:24 Comm. failure # Slave 1

03/17 14:24 Alarm Type # RS485Comms (24)

03/17 14:25 Comm. restore # Slave 1

....repeating forever.

It could be because one of the slaves has developed a fault in the rs485 driver
Try disconnecting a slave and see if the problem stops, ie you wil get a permanent comms failkure because of the disconnected slave
This is to identify which slave causes the problem

Hi Chiu.
Connecting one slave at a time to the main board changes nothing. Both seems to have problems.
But... Connecting one slave at a time to the main board using the 4 pole cable instead of the KA KB 2 pole connection, seems to solve the issue. Both slaves works.
It is strange, because the keypads works flawlessy with KA KB cable.

There may be a partial short on the ka kb wires
Disconnect and measure resistance between them

Hi Chiu,
for now, i solved by re-wiring a \"COM\" cable (the negative pole of the 12V power socket) between Slave 1, Slave 2 and Main board.
For an unknown reason, this wire was come out from the socket of the Main board.
I\'ve been restored the connection through KA KB cable and both slaves seems to work normally now.

By looking closely to the wire, i\'m sure that for a long period of time, the connection was ok, even without the negative ground connecting all slaves and the Main board.
Is that possible?

It is possible that the communication can work even without the COM cable but it may be intermittent

TheMax74

slychiu

TheMax74

slychiu

TheMax74

slychiu