BARTINGTON INSTRUMENTS
Page 47 of 61 OM1800/26
2
Position in the Y
direction in metres.
The Y direction
represents the spacing
between traverses.
So that the plotted values correspond with the
spreadsheet view, the first traverse represents the
maximum value of Y and the last traverse corresponds
to the minimum value of Y.
Assuming the first traverse starts at the top left of the
Grid then
X=min, Y=min
therefore represents the bottom
left of the Grid;
X=min, Y=max
represents the top left;
and
X=max, Y=max
represents the top right.
3
Z, the gradient
measured in nT at that
point
n/a
20. Serial Output
The DL601 Data Logger outputs the data from memory via a three-line RS-232 interface (TX, RX
and Gnd). When
Output data
is selected from the main menu, the data logger will turn on the RS-
232 interface and wait until the character S is received from the PC before starting transmission.
The gradiometer will then transmit 32 signed integers as 64 bytes and wait for the next character
S from the PC.
The baud rate is set to 9600 baud with 8 data bits, no parity, 1 stop bit and no handshaking. The
last transmission may be less than 64 bytes.
20.1. Data Format
The data represents a number of Grids. The data file for each Grid comprises a header, the
gradiometer readings and summary information. An End of Transmission integer and a
final checksum follows the data for the final Grid. All data is saved in the gradiometer and
subsequently output in binary (signed integer) format, 2 bytes per integer, MSB first. All data is
translated into ASCII characters in the PC after receipt.
The gradiometer has ranges of
±
100nT and
±
1000nT denoted by values of 1 and 10 respectively
in the header information. Data is transmitted as signed integers in the range
±
10,000,
representing values of
±
100.00nT for the
±
100nT range and
±
1,000.0nT for the
±
1000nT range.
The download software inserts the decimal point at the appropriate place. Integers above 32000
are used for markers in the data stream.
20.2. Markers
The following specific integers are reserved for markers.
