VMB4RY support

I have just plugged in a new VMB4RY and am having problems with it…

When the module address is set to 0.0, all works as expected.

With the module addres address set to any other (non-learning) address, for instance 2.1, the following happens:

When power is applied, the Rx/Tx lights flash fast for about 30 seconds. This is followed by eight double flashes of all four Ch(x) LEDs before the Rx/Tx LEDs flash quickly again and the cycle restarts.

I have tried the module with or without another module on the bus (when another module is connected, the orher module’s Rx LED flashes when the VMB4RY’s Rx and Tx LEDs are flashing) and with and without the termination jumper set.

The module is receiving a measured 12.948v from a regulated PSU. The resistance across the bus pair (measured with the module’s power disconnected) is 218O with the termination jumper in place and 48KO without.

Please advise or let me know if there is any ohter information I can give.


This is normal behaviour. If you use the unit without any other Velbus item connected, you must set it to 00, otherwise it will continuously try to detect other Velbus modules. If you use it with other Velbus items, make sure each item has a different address and different from 00.

Oops. I was trying to use it with only a USB interface module for company but hadn’t realized this wouldn’t be “alive” until the USB had power, as well as the module. My poor little VMB4RY was lonely!

Thanks for your help.