Basic Message Structure - Christie Crimson Technical Reference

Basic message structure

Understand the component fields that comprise a standard ASCII message.
Components
Start and end of message
Prefix characters (optional) To acknowledge that Crimson has responded, and/or maximize message integrity,
Function code
+Subcode
Request/reply symbols
Data
Crimson and Crimson Mirage Technical Reference–Serial Commands
020-102660-01 Rev. 1 (07-2018)
Copyright 2018 Christie Digital Systems USA, Inc. All rights reserved.
©
Description
Every message begins with the left bracket character and ends with the right bracket
character.
If the start character is received before an end character of the previous message,
the partial (previous) message is discarded.
insert one or two special characters before the three-character function code:
• $ (Simple Acknowledgment)—Causes a dollar sign ($) character to be sent from
Crimson when it has finished processing the message.
• # (Full Acknowledgment)—Causes an echo of the message as a reply to be sent
from Crimson when it has finished processing the message.
• & (Checksum)—Allows a checksum to be put as the last parameter in the
message for verification at Crimson.
The Crimson function you want to work with, such as channel selection or gamma, is
represented by a three-character ASCII code (A-Z, upper or lower case). This
function code appears immediately after the leading bracket that starts the message.
In messages sent to Crimson that do not have a subcode, a space between the
function code and the first parameter (or special character) is optional.
The Crimson function you want to work with may have one or more subcodes that
allow you to select a specific source, image, channel or subfunction.
The subcode is represented by a four-character ASCII code (A-Z, upper or lower
case, and 0-9). This subcode appears immediately after the function code, with a
plus sign (+) character to separate the code and subcode. If there is no subcode, the
plus sign (+) is also omitted. In messages sent to Crimson that have a subcode, a
space between the subcode and the first parameter (or special character) is optional.
If the controller is requesting information from Crimson, a question mark (?) appears
directly after the function code. If Crimson is replying, an exclamation mark (!)
appears directly after the function code. For set messages to Crimson, neither of
these characters appear—data directly follows the code and subcode.
A request for information is represented by a question mark (?) that appears directly
after the function code. A reply is represented by an exclamation mark (!) that
appears directly after the function code or subcode, if one is provided. The first
parameter located after the exclamation mark (!) reply character cannot have a
space, for example (PWR!000).
The value for a given Crimson state, such as on or off, appears in ASCII-decimal
format directly after the request/reply symbol. You can add an optional space after
the symbol—such as before the data—in a set message, but data in replies follow the
exclamation mark (!) symbol without a space. Other details to remember about
data:
• All values returned by Crimson (reply messages) have a fixed length, regardless
of the actual value. For a specific parameter, the length is always the same (for
example, contrast is always returned as three characters, Crimson number is
always returned as five characters). The minimum parameter size is three
Communicating with Crimson
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