User Manual

A.5 Receiving API Feedback
The LPU-2 is capable of sending messages back to the external control system
when communicating via OSC or UDP. As soon as the LPU-2 receives a com-
mand via OSC or UDP it will store the IP and port of the external system in
a list. When a status changes inside the LPU-2 (e.g. a playback gets released)
then all ’clients’ in this list will receive a message indicating the new status.
The LPU-2 can store a maximum of four OSC clients plus four UDP clients.
This internal client list will be cleared by a power-cycle.
The ’hello’ command can be used to poll the LPU-2. The LPU-2 will respond
to a incoming Hello by sending a Hello message back to the client.
Clients can also get the current levels of certain properties. Some properties (e.g.
playback intensity) can be polled by sending the command message without a
parameter. For example, the following UDP command will get the speed level of
playback 9: pb09/spd The LPU-2 will now reply with pb09/spd=-0.5 indicating
the speed level is at -50%.
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