# Channel Status Messages

All channel types have two distinct text messages available as well as two corresponding distinct voice messages for use in delivering reports to destinations. A data mode report may include one or both available text messages, while a corresponding voice mode report can also use one or both available voice messages.

For both text and voice reports the specific way in which the RTU makes use of these two messages depends upon whether the channel is configured as analog type (having a continuous range of possible values), or discrete type (having just two possible values, 0 and 1).

Analog Channels

Analog channel reports use the two messages (in this case, message segments) to create a composite message consisting of:

"Message 1" + Analog Reading + "Message 2" + Current STATE

A leading preamble message (Message #1)

Followed by the current analog reading

Followed by an epilogue message (Message #2)

Followed by the current channel state

The general form of this composite message would be as illustrated in this example:

"Water Tank Level is" "213" "Feet" "NORMAL."

“Water Tank level is 213 Feet NORMAL”

Discrete Channels

Discrete channel reports use the two descriptive messages to reflect the two different possible current values:

- If the current reading value is 0, Message #1 is used for the channel status message.
- If the current reading value is 1, Message #2 is used for the channel status message.

Example:

If the current reading value is 0, "The Main Pump is ON."

If the current reading value is 1, "The Main Pump is OFF."

Looking at this distinction another way, for analog channels, the immediately current reading value determines the analog value that is inserted between the two messages. For discrete channels, the immediately current reading value determines the choice of the two messages that are to be used.

Important Note: Channel status reports include not only the above described messages which reflect the channel's value, but also Tag Word(s) which reflect the channel's state (ALARM, NORMAL, etc.), and which are automatically appended to the messages to complete the report. Therefore these messages should be crafted with that fact in mind.

See Also

Channel State Changes

Tag Words and Channel States

Tag Words for Discrete Channels

Tag Words for Analog Channels

Remaining Tag Words