EIB power supply.

[mike]

This is so funny .

I've only opened some older power supplies and there I could see that they follow this characteristic (by the capacitors and the transformer had an extra output and the like).

Thanks for this picture!

Mike

[MatthiasS]

This sounds very complicated

If we have a look at this powersupply from L&J, I wonder where this specific behaviour comes from?

[mike]

Not only certification!

A "real" KNX power supply has a specific characteristic on power down. KNX nodes detects a power failure by measuring the voltage. If the voltage drops below a specific value, the KNX node assumes that the power goes down. The node can then save some values into persistent memory. For that it needs power. Therefore the knx power supply has to keep the voltage stable at this low value for a specific amount of time.

A normal power supply doesn't has this characteristic. If the node begins to write into persistent memory the power gets lost and the node may have written only partial configuration which may lead to problems on power up.

Now it depends on how many nodes you have which really wants to store values into persistent memory. I think in my installation I have no such device.

Mike

[MatthiasS]

Certification

[McKajVah]

What is the difference between this and a "KNX-certifed" solution, price only?

[Hennessy]

This is exactly what I was using for my test setup one year ago, prior to moving. Works fine, but is not a KNX-certified solution.

[McKajVah]

Is it possible to use this PHOENIX CONTACT powersupply together with a choke to power the EIB-bus? You can change the voltage from 21-29.5V

I'm thinking of using 2 powersupplies to have a redundant setup, and this solution would be much cheaper.

-Kaj