Rose Electronics QuadraVista QF - Manual (Page 54)

48 QuadraVista Installation and Operations Manual
timeout Receive timeout. This error message is displayed if a DCP
message is not complete after expiry of the timeout, but no other
error has occurred.
parser stack overflow
This error occurs when unknown elements are nested too deeply,
or in the case of an internal error.
internal parser error
Internal error parser error.
unknown error
Unknown error.
DCP Communication
DCP/XML messages exceeding 38 characters must be divided into individual lines before being sent to a
device.
Replies sent by a device are also divided into lines.
When sending a DCP message, the following constraints apply:
Linefeed: LF
Linefeed (0x0A) is used as terminating character of each line.
Whitespace: TAB, SPACE, CR
Whitespace characters are TAB (0x09), Space (0x20) and Carriage Return (0x0D).
Whitespace may occur anywhere between two tags, except at the start of a line and inside simple
elements
Whitespace is ignored.
Line length: maximum 38 characters
The line length may not exceed 38 characters.
(Not including the terminating LF.)
Timeout: 750 ms
Timeout for DCP messages is 750 milliseconds.
DCP messages containing errors are not regarded as completed until the timeout period has
elapsed.
Therefore, it is recommended to wait for this time between DCP messages to allow the parser to
handle possible errors.
Correct messages are processed immediately upon completion.
Unknown elements
Unknown tags in a DCP message are ignored for the sake of upwards compatibility of the protocol.
Messages containing unknown elements must still be syntactically correct.