Using the DM24
•
Z
,
N
, and
E
denote the vertical, north/south, and east/west components
respectively.
•
X
denotes the fourth full-rate data channel, which is provided for connection
to your own monitoring equipment via the
AUXILIARY
connector (if present).
•
C
denotes the calibration input channel, which replaces the
X
stream whilst
calibration is in progress.
•
M
denotes one of the eight slow-rate Mux (multiplex) channels. Three of these
(
M8
,
M9
and
MA
) are used to report the sensor mass positions. Channels
MC
and
MD
are connected to the X and Y axes of the downhole inclinometer, where
fitted.
•
For
Z
,
N
,
E
,
X
, and
C
streams, the last character represents the output tap. Taps
correspond to stages in the decimation process within the digitiser, allowing
the DM24 to output several different data rates simultaneously. There are
four taps, numbered 0 to 3; 0 has the highest data rate and 3 the lowest. Data
streams end in
0
,
2
,
4
and
6
for taps 0, 1, 2 and 3 respectively.
If you configure the DM24 to output triggered data, these will appear in
separate streams ending with the letters
G
,
I
,
K
or
M
for taps 0, 1, 2 and 3
respectively.
The DM24 also generates a stream ending
00
. This is a status stream containing
useful diagnostic information in plain text form (see Section 7.1 on page 95).
4.2.1 Digitisers for multiple instruments
The standard DM24 has 4 full-rate channels: one per component of a triaxial
instrument, plus the auxiliary and calibration channel.
Some DM24 modules, known as “6-channel digitisers”, are designed for use with two
instruments simultaneously, connected to the ports
SENSOR A
and
SENSOR B
.
These digitisers actually have 7 full rate data channels, including the
auxiliary/calibration channel. When you enable calibration on these digitisers, the
signal is passed to both instruments. All 7 channels share the same settings for the
four output taps.
18
Issue U - December, 2021
