HEKA EPC 9 - Page 95

Controlling E9Screen EPC9 Installation 95
END; (* IF *)
IF NOT
IOText.Open(
MessageName,
IOFiles.Read + IOFiles.Shared,
MessageFile )
THEN
IF IOFiles.GetError() <> IOFiles.FileNotFound THEN
WriteError( 'Opening message file' );
END; (* IF *)
RETURN FALSE;
END; (* IF *)
LastSignature := -1;
RETURN TRUE;
END OpenMessageFile;
PROCEDURE PollForCommands;
VAR
InputString : ARRAY[0..127] OF CHAR;
NewSignature : INTEGER;
Count : INTEGER;
Dummy : BOOLEAN;
BEGIN
IF NOT CommandFile.IsOpen THEN
RETURN;
END; (* IF *)
IF ( NOT MessageFile.IsOpen ) AND ( NOT OpenMessageFile() ) THEN
RETURN;
END; (* IF *)
(* Read the first text line. If reading fails, or converting to a number
fails, or the resulting number is negative, then the answer from the
target E9Screen is not ready.
*)
NewSignature := -2;
Count := HIGH( InputString );
IF
( NOT IOText.SetPosition( MessageFile, IOFiles.FromStart, 0 ) ) OR
( NOT IOText.Read( MessageFile, Count, ADR( InputString ) ) )
THEN
RETURN;
END; (* IF *)
IF ( InputString[0] = 0C ) OR ( InputString[0] = '-' ) THEN
RETURN;
END; (* IF *)
Count := Encode.Integer( InputString, NewSignature );
IF ( NewSignature < 0 ) OR ( LastSignature = NewSignature ) THEN