Fluke ScopeMeter 190 Series, Programming Reference Manual

Page: 58 / 120

PRINT #1, "PC 1200" ’Programs ScopeMeter back to the
’default baud rate.
GOSUB Acknowledge ’Input acknowledge from ScopeMeter.
CLOSE #1
PRINT "Print data copied to file ’SCREEN.PNG’."
PRINT "You can use a browser program or a graphics editor"
PRINT "to view this file."
END
’****************** ReadBlock subroutine *********************
’This subroutine reads one block of data from the RS232 port.
’The actual data bytes received (i.e., excluding the block
’header, checksum and acknowledge bytes) are stored in the
’string BlockData$.
’LastBlock% indicates whether the received block is the last
’one (1) or not (0).
ReadBlock:
PRINT #1, "0" ’Request the next data block.
GOSUB Acknowledge ’Input acknowledge from ScopeMeter.
BlockHeader$ = INPUT$(5, #1) ’Read the block header.
IF LEFT$(BlockHeader$, 2) <> "#0" THEN
PRINT "Block transfer protocol error."
CLOSE ’Close all files.
PRINT "Program aborted."
END
END IF
IF (ASC(MID$(BlockHeader$, 3, 1)) AND 128) = 128 THEN
LastBlock% = 1 ’This is the last block.
ELSE
LastBlock% = 0
END IF
BlockLenHigh% = ASC(MID$(BlockHeader$, 4, 1))
BlockLenLow% = ASC(MID$(BlockHeader$, 5, 1))
BlockLength& = (256 * BlockLenHigh%) + BlockLenLow%
BlockData$ = INPUT$(BlockLength&, #1) ’Read the block data.
CheckSum$ = INPUT$(2, #1) ’Read the checksum
ReceivedCheckSum% = ASC(LEFT$(CheckSum$, 1))
CalculatedCheckSum% = 0
FOR I& = 1 TO BlockLength&
Byte% = ASC(MID$(BlockData$, I&, 1))
CalculatedCheckSum% = CalculatedCheckSum% + Byte%
CalculatedCheckSum% = CalculatedCheckSum% MOD 256
NEXT I&
IF CalculatedCheckSum% <> ReceivedCheckSum% THEN
PRINT "Checksum error"
PRINT #1, "2" ’Terminate (abort) QP command.
’(We could send "1" instead to request