Fluke ScopeMeter 190 Series, Programming Reference Manual

Page: 55 / 120

Page 3.40
Response Syntax for QP 0,11,b or QP 0,11,B:
<acknowledge><cr><png_data_length>,<png_data>
where,
<png_data_length> = <digit>{<digit>}
This field indicates the total number of
bytes in the <png_data>.
<png_data> = <segment>{<segment>}
<segment> = <acknowledge><cr>#0<block_header><block_length>
<block_data><check_sum><cr>
<block_header> = <binary_character>
When the most significant bit (bit 7) is set,
this block (segment) is the last one in the
sequence.
<block_length> = <unsigned_integer>
Specifies the number of <binary_character>’s
that follow in the <block_data> field.
<block_data> = {<binary_character>}
Part of the graphics (PNG) data.
<check_sum> = <binary_character>
One binary character which represents the sum
of all the <binary_character>’s sent after
the <block_length> and before the <check_sum>.
The <png_data> is sent in blocks (segments). When the <block_data>
parts of all <segment>’s are concatenated, they form a PNG-format
graphics file of length <png_data_length> bytes.
The instrument has to be prompted for every block (segment):
Command syntax for block transfer:
<segment_acknowledge><cr>
where,
<segment_acknowledge> = 0 Continue: Request the next segment.
1 Retransmit: Request retransmission
of the just transferred segment.
2 Terminate: Abort block transfer for
this QP command.
The PNG format is specified in: "PNG (Portable Network Graphics)
Specification, Version 1.2", G. Randers-Pehrson et al. (PNG
Development Group), July 1999; This document is available from
www.libpng.org/pub/png/.
The PNG file consists of the following chunks: