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CANBus Networking Manual
19
RoboCAN via Serial & USB
Realtime Queries
Queries are handled the same way but the reply to a query includes the responding
node’s address. Below is a Query example:
?V 2
This is the normal query for reading the battery voltage of the local controller. The control-
ler will reply V=123
@04?V 2
This will send the same query to node address 4
The reply of the remote node is @04 V=123
Replies to remote nodes queries are identical to these to a local controller with the excep-
tion of an added latency. Since the reply must be retrieved from the remote node depend-
ing on the selected bit rate, the reply may come up to 10ms after the query was sent.
Remote Queries restrictions
Remote queries can only return a single value whereas local queries can be used to read
an array of values. For example
?AI
Is a local query that will return the values of all analog capture channels in a single string
as
AI=123:234:345:567
@04?AI
Is a remote query and it will return only the first analog capture channel as
@04 AI=123
Remote queries are not being added in the Query history.
Broadcast remote queries are not supported. For example @00?V 1 will not be executed.
Queries that return strings, such as ?FID or ?TRN are not supported. They will return the
value 0
See the Command Reference section in the manual for the complete list and description
of available queries