# How the local message display works

Use a local message display to give the operator prompts about what to do next or information about a process.

At run time the local message display shows one message at a time from the message file you assigned to the local message display. The application monitors the Value connection at the data source, and shows the message with the trigger value that matches the Value connection value.

Tip: | A message file contains a list of messages with a trigger value for each message. Set up the message files in the Local Messages editor.

## Message File

When you open a graphic display at run time, the application checks whether a valid local message file is referenced. If no message file is selected, or the selected message file is corrupt or does not exist, the following message shows on the local message display:

"Referenced Local Message file is missing or corrupt."

You can select a local message file at design time, or use a variable message file and select a local message file at run time.

## Value connection

When you open a graphic display at run time, if the referenced local message file is valid, the application reads the Value connection value and updates the local message display object based on the value.

If the Value connection value is 0, the local message display is cleared.

If the Value connection is unassigned, or the Value connection value does not match any of the trigger values in the specified message file, question marks (?) shows on the local message display.

## Echo message

When the echo message function is used, the triggered message will be written to the string tag assigned to the Echo Message connection.

The echo message function works whether the local message display object is visible or hidden at run time.

## See also

Create a local message display

Create local messages

Options on the General tab of the Local Message Display Properties dialog box

Set up connections for a local message display