I have this problem I simply associated 4 buttons with 4 relays on VMB4RYNO, single activation all right, but when all 4 are active after a few seconds go off (are programmed toogle), someone can help me I Version 9 Velbuslink 9.84, 0.3
Thanks for your help

paolo spagnolo


I had something similar with a batch of VMB1BLS that I installed at the rear of a customer’s property… On the end of a long length of cable…

When more than 1 blind (relay) was activated, they would release at random times.

It took me months to realise that what was happening was that the bus voltage was dropping due to the extra demand due to the relay coils.

(The same happens with VMB4RYNO & VMB4RYLD when I tested them)

My solution was to raise the bus voltage.

So that over distance, the modules were still getting the minimum 12v.

I had a similar experience with a pair of VMB4RYLD in a boiler room (which were controlling heating zones), in that situation I put a local power supply in that cabinet to power ONLY those relays.

As per the guidelines in the installation documents, this is totally acceptable, as long as the new +12~18v is seperated from the rest of the network.

(Keep… 0v, Bus High & Bus Low connected)

Short answer…

Check the bus voltage at the modules that are displaying these symptoms, both at rest and moments before the relays drop out.

Many Thnaks
maybe it’s just a tension problem I try immediately

1 Like

You’re welcome.

How did you get on?

power ok I made a reset by default, but when I try to operate manual one by one the relays, when the fourth is activated after 3/4 seconds all are turned off. new project all at default and no programmed button or time, what is possibly a failed module?

sorry for delay