PDL size and manufacturer specific parameter ID's
Greetings,
This is a question regarding an RDM controller generating GET and SET messages for manufacturer specific parameter ID's, based on the information obtained from using the PARAMETER_DESCRIPTION command.
The response to a PARAMETER_DESCRIPTION command includes the "PDL Size" field, which corresponds to GET_RESPONSE and SET PDL sizes, but what about GET and SET_RESPONSE PDL sizes??
Example:
Get/Set DMX Curve command
GET takes in channel (PDL size = 1)
GET_RESPONSE replies with channel and curve (PDL size = 2)
SET takes in channel and curve (PDL size = 2)
SET_RESPONSE replies with no data (PDL size = 0)
So the PDL size field under PARAMETER_DESCRIPTION would be 2 to match GET_RESPONSE and SET, but there is no indication as to how much data to use with GET.
Has anyone come up with a solution/workaround for this?? Note that the controller I'm developing is hand-held with limited firmware, so it's not feasible storing the required information for manufacturer specific id's.
One possible workaround I've thought about is first attempting GET with a PDL size the same as GET_RESPONSE/SET (after allowing the user to set as many data fields as they like up to the GET_RESPONSE/SET PDL size), and if a NACK is received, keep reducing the PDL size of GET until an ACK is received.
Any thoughts on this would be greatly appreciated.
Regards,
Jamie.
Creative Lighting
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