LSS100300 Spacelogic KNX BMS Gateway shows incorrect status of devices after startup or power failure

[ranla]

Hi,

We started using the Spacelogic KNX BMS IP Gateway (LSS100300) about a year ago, instead of the Spacelynk gateway (LSS100200) in our projects that only require sending knx data to Ecostruxure Builiding Operation devices via bacnet/IP without graphics.

However, there is a feature that exists in the spacelynk device, that doesn't seem to exist in the BMS gateway and is creating big issues for us.

In the Spacelynk device, there is an option to tick in the group address settings "read on startup".

So basically if the device  itself restarts for some reason, or if there is a temporary power  failure, upon startup it reads the correct status of the KNX devices group addressees that were selected to be read, and displays the correct status, also on the bacnet server.

This option doesn't seem to exist in the BMS gateway, and several clients have pointed this issue to us, that the status isn't correctly displayed

Is there any plan to implement this ? 

we need a solution.

Thanks,

Ron

[Erwin-vd-Zwart · Accepted solution]

The LSS100300 is a gateway and not a controller, so what it does is exactly what you might expect from it, it transfer KNX <-> BACnet without any additional actions.

When a KNX telegram is missed due to a system failure the telegram has to be send again, that is why cyclic sending exists.

If you need a device to execute read request you need a controller and not a gateway, due to this additional functionality you need a more expensive device (controller)

[ranla]

Hi Erwin,

Thanks for the quick response.

I understand what your are saying, however it doesn't seem right that if the gateway has some kind of failure, it can't execute some type of read operation on startup.

I dont think this is a functionality that is expected only from a controller.

The solution of sending hundreds of telegrams cyclicly on the bus every few minutes when all we need is 1 read on startup is a bit of an overkill, and will just congest the bus.

We would appreciate you considering adding this feature in future firmware updates if possible.

[Erwin-vd-Zwart]

Any action other then passing data from A <-> B is taking control, hence controller functionality, i already asked R&D as i agree that it could make sense, first reaction was same as mine, you need a controller and not a gateway when you want to execute control actions.

If you compare it with any other gateway (Modbus/BACnet/DMX or likewise) you face the same issue, a gateway never perform actions by itself.

Same counts for KNX IP routers, when a KNX IP router is down for whatever reason it won't perform read requests on startup so you will have same issue in that KNX segment. You could consider backup solutions like a panel UPS to avoid downtime of a gateway.

Otherwise your solution is known, use a SL controller instead of a gateway.