View Single Post
Old July 21st, 2006   #2
Task Group Member
Join Date: Jul 2006
Posts: 10
Default You would respond

I am not Scott, and can’t quote RDM off the top my head. However, I think this question has gotten several different messages confused. Or I don’t understand the question . . .

The ONLY command sent with a broadcast address that is EVER responded to is ‘Discovery Unique Branch’(7.5) A responder only responds if:
a) The responder is un-muted
b) The responder’s UID is within the address range asked for in the ‘Dis Unique Branch Message’. It responds only with the special message of TABLE 7-1.

The Discovery Mute Message (7.6) only responds to a non broadcast message sent to its UID, if asked it should respond. If it responds due to an apparently valid but in fact corrupt mute message, this fact will be apparent to the controller because the response contains a source UID. The controller should always check to see that any response comes from the expected place. (NOTE it may ACT, IE mute in response to a broadcast message.)

A response to a mute message says nothing about the presence of other devices in an address range. It simply confirms that a particular device is at a specific UID and has muted.

‘Discovery Unique Branch’ must continue to probe an address range until there are no ‘Discovery Unique Branch Response’ messages, the format of which is laid out in table 7-1. It should be expected that you sometimes mute a real device but not the one you expected.

I hope this helps.
Bob Goddard
Goddard Design Co.
R_Goddard is offline   Reply With Quote