LSS100300 Power

[DiegoC]

Hello Community.

I wanted to ask you about the LSS100300 gateway. Every time this gateway is used, the KNX output is 24V and not 30V. How does this connection work? Are they 24V power supplies in series? We should get 30V and not 24V at the KNX output

Thanks!

[Thomas_Rohde · Accepted solution]

Hi DiegoC!

To "Every time this gateway is used, the KNX output is 24V and not 30V. How does this connection work?"
A normal KNX-Powersupply, with no loads connected, will have 29-30V. As soon as you connect devices, the voltage level will drop slightly depending on the amount of devices and their consumption (Not taken the cable length into consideration).
The busvoltage can go down to a minimum level of 21V. Means, 24V will work without any problem.
Of course the amount of connected KNX-Devices is limited.
If you prefer to have a higher voltage level within your installation, you can use a normal KNX-Powersupply INSTEAD of using the 24V Input of LSS100300.
The 24V aproach is just made to save some costs of a real KNX Powersupply especially when there are only a few KNX devices connected.

To "Are they 24V power supplies in series? We should get 30V and not 24V at the KNX output"
No, in case of two powersupplies connected (which is just optional), they will work in parallel mode. 

[DiegoC]

Ok... The spec sheet says 24 to 31V. Great, Thomas! Excellent and thanks for the explanation.

Regards,