Maple Systems MAP450D - Manual (Page 28)

Displaying Text from Predefined Messages
In some applications, the OIT may be required to display many messages to the OIT
operator concerning the state of the control system. If these messages are always the
same, they can be stored in the OIT and displayed whenever the host controller requests
them. The OIT has the ability to store up to 500 predefined messages. Each predefined
message can be as long as the number of characters per line on the OIT and can contain
printable ASCII characters and characters from the extended character set.
To display a predefined message, the host controller sends the Display Message control
command (
ESC
m message# terminator). When the OIT receives the Display Message
control command, the requested message displays at the OIT cursor’s current location. If
the message is longer than the number of character spaces remaining on the current
display line, the message is truncated, unless word wrap is enabled. Refer to Appendix A:
Control Commands for more information on the Display Message control command.
Optional Settings for Predefined Messages
Each predefined message can be configured with optional controls which the OIT will
perform either before or after a message is displayed on the OIT screen. These controls
are provided to minimize the amount of commands that must be sent from the host in
order to format the OIT display screen.
Controls used before displaying the message: Each predefined message can be tagged
with one of the following controls. These controls are performed on the OIT before the
message is displayed:
• No Action - selecting this option means that nothing is done to the OIT display before the pre-
defined message is displayed.
• Clear Screen - the OIT clears the entire screen and homes the cursor.
• Clear Line - the OIT clears the entire line that the cursor is located on and moves the cursor to
the beginning of the line.
• Clear to End of Line - the OIT clears the entire line starting at the current position of the cursor.
Controls used after displaying the message: Each predefined message can be tagged
with one of the following controls. These controls are performed on the OIT display after
the message is displayed:
• No Action - selecting this option means nothing is done to the OIT display after the predefined
message is displayed.
• CR (Carriage Return) - the OIT moves the cursor to the beginning of the line that the cursor is
on after the message is displayed.
• LF (Line Feed) - the OIT moves the cursor to the beginning of the next line after the message is
displayed.
• VT (Vertical Tab) - the OIT performs a ‘reverse line feed’ by moving the cursor to the begin-
ning of the previous line after the message is displayed.
• Cursor to Start of Msg - the OIT moves the cursor to the first character of the message that was
just displayed.
27 MAP450D Operation Manual
1010-0101, Rev. 00