This waits for a key press from the display. The function waits for a maximum number of seconds, and if no key is pressed within the timeout period, the function returns a 0 which indicates the timeout. If a key press has been detected before the timeout period, a number identifying the actual key press is returned.
A small buffer is present in the system so that all key presses are received by the application.
Input:
timeout : INT
-1
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- Waits forever until a key is pressed.
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0
|
- Does not wait.
|
> 0
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- Waits the specified number of second (max. 60).
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Returns:
-2
|
- Invalid parameter.
|
-1
|
- Not supported.
|
0
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- Timeout.
|
120
|
- Up arrow key pressed.
|
121
|
- Down arrow key pressed.
|
122
|
- Left arrow key pressed.
|
123
|
- Right arrow key pressed.
|
124
|
- OK key pressed.
|
125
|
- ESC key pressed.
|
126
|
- DEL key pressed.
|
127
|
- SEL key pressed.
|
200
|
- NX-400 only: Click happened on screen where there was no control to handle it.
|
201
|
- NX-400 only: Click happened on status bar where there was no control to handle it.
|
202
|
- NX-400/LX4 only: Backlight reduced due to inactivity. See displayPower for more information.
|
203
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- NX-400/LX4 only: Activity has occurred; the backlight is restored.
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Declaration:
FUNCTION displayGetKey : INT;
VAR_INPUT
timeout : INT;
END_VAR;
Example:
INCLUDE rtcu.inc
PROGRAM test;
VAR
key : INT;
END_VAR;
BEGIN
...
key := displayGetKey(timeout := 45);
...
END;
END_PROGRAM;
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