Campbell Manufacturing CR10 Manual De Usuario
SECTION 2. INTERNAL DATA STORAGE
2-4
NOTE: All memory pointers are set to the
DSP location when the datalogger
compiles a program. For this reason,
ALWAYS RETRIEVE UNCOLLECTED
DATA BEFORE MAKING PROGRAM
CHANGES. For example, assume the
TPTR lags the DSP by less than 512 data
points when the datalogger program is
altered. On compiling, the TPTR is
positioned with the DSP, losing reference
to the data that was intended to be
transferred to tape. The data is not
automatically transferred and appears as a
discontinuity in the data file. Until the ring
memory wraps around and data overwrite
occurs, the data may be recovered using
the *8 Mode. This scenario is also true for
the SPTR and data intended for a Storage
Module.
DSP location when the datalogger
compiles a program. For this reason,
ALWAYS RETRIEVE UNCOLLECTED
DATA BEFORE MAKING PROGRAM
CHANGES. For example, assume the
TPTR lags the DSP by less than 512 data
points when the datalogger program is
altered. On compiling, the TPTR is
positioned with the DSP, losing reference
to the data that was intended to be
transferred to tape. The data is not
automatically transferred and appears as a
discontinuity in the data file. Until the ring
memory wraps around and data overwrite
occurs, the data may be recovered using
the *8 Mode. This scenario is also true for
the SPTR and data intended for a Storage
Module.
2.2 DATA OUTPUT FORMAT AND
RANGE LIMITS
Data is stored internally in Campbell Scientific's
Binary Final Storage Format (Appendix C.2).
Data may be sent to Final Storage in either LOW
RESOLUTION or HIGH RESOLUTION format.
Binary Final Storage Format (Appendix C.2).
Data may be sent to Final Storage in either LOW
RESOLUTION or HIGH RESOLUTION format.
2.2.1 RESOLUTION AND RANGE LIMITS
Low resolution data is a 2 byte format with 4
significant digits and a maximum magnitude of
+6999. High resolution data is a 4 byte format
with 5 significant digits and a maximum
possible output value of +99999 (see Table 2.2-
1 below).
significant digits and a maximum magnitude of
+6999. High resolution data is a 4 byte format
with 5 significant digits and a maximum
possible output value of +99999 (see Table 2.2-
1 below).
TABLE 2.2-1. Resolution Range Limits of
CR10 Data
Minimum
Maximum
Resolution
Zero
Magnitude Magnitude
Low
0.000
+0.001
+6999.
High
0.0000
+ .00001
+99999.
The resolution of the low resolution format is
reduced to 3 significant digits when the first (left
most) digit is 7 or greater. Thus, it may be
necessary to use high resolution output or an offset
to maintain the desired resolution of a measurement.
For example, if water level is to be measured and
output to the nearest 0.01 ft., the level must be less
than 70 ft. for low resolution output to display the
0.01 ft. increment. If the water level was expected
to range from 50 to 80 feet the data could either be
reduced to 3 significant digits when the first (left
most) digit is 7 or greater. Thus, it may be
necessary to use high resolution output or an offset
to maintain the desired resolution of a measurement.
For example, if water level is to be measured and
output to the nearest 0.01 ft., the level must be less
than 70 ft. for low resolution output to display the
0.01 ft. increment. If the water level was expected
to range from 50 to 80 feet the data could either be
output in high resolution or could be offset by 20 ft.
(transforming the range to 30 to 50 ft.).
(transforming the range to 30 to 50 ft.).
2.2.2 INPUT AND INTERMEDIATE
STORAGE DATA FORMAT
STORAGE DATA FORMAT
While output data have the limits described
above, the computations performed in the
CR10 are done in floating point arithmetic. In
Input and Intermediate Storage, the numbers
are stored and processed in a binary format
with a 23 bit binary mantissa and a 6 bit binary
exponent. The largest and smallest numbers
that can be stored and processed are 9 x 10
above, the computations performed in the
CR10 are done in floating point arithmetic. In
Input and Intermediate Storage, the numbers
are stored and processed in a binary format
with a 23 bit binary mantissa and a 6 bit binary
exponent. The largest and smallest numbers
that can be stored and processed are 9 x 10
18
and 1 x 10
-19
, respectively. The size of the
number determines the resolution of the
arithmetic. A rough approximation of the
resolution is that it is better than 1 in the
seventh digit. For example, the resolution of
97,386,924 is better than 10. The resolution of
0.0086731924 is better than 0.000000001.
arithmetic. A rough approximation of the
resolution is that it is better than 1 in the
seventh digit. For example, the resolution of
97,386,924 is better than 10. The resolution of
0.0086731924 is better than 0.000000001.
A precise calculation of the resolution of a
number may be determined by representing the
number as a mantissa between .5 and 1
multiplied by 2 raised to some integer power.
The resolution is the product of that power of 2
and 2
number may be determined by representing the
number as a mantissa between .5 and 1
multiplied by 2 raised to some integer power.
The resolution is the product of that power of 2
and 2
-24
. For example, representing 478 as
.9336 * 2
9
, the resolution is 2
9
* 2
-24
= 2
-15
=
0.0000305. A description of Campbell Scientific's
floating point format may be found in the
description of the J and K Telecommunications
Commands in Appendix C.
floating point format may be found in the
description of the J and K Telecommunications
Commands in Appendix C.
2.3 DISPLAYING STORED DATA ON
KEYBOARD/DISPLAY - *7 MODE
(Computer/terminal users refer to Section 5 for
instructions on entering the Remote Keyboard
State.)
instructions on entering the Remote Keyboard
State.)
Final Storage may be displayed by using the *7
Mode. Key *7.
Mode. Key *7.
If you have allocated memory to Final Storage
Area 2, the display will show:
Area 2, the display will show:
07:00
Select which Storage Area you wish to view:
00 or 01 = Final Storage Area 1
02 = Final Storage Area 2