Campbell CR10 PROM, Руководство оператора

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2-1
SECTION 2. INTERNAL DATA STORAGE
2.1 FINAL STORAGE AREAS, OUTPUT
ARRAYS, AND MEMORY POINTERS
Final Storage is that portion of memory where
final processed data are stored. It is from Final
Storage that data is transferred to your
computer or external storage peripheral.
The size of Final Storage is expressed in terms of
memory locations or bytes. A low resolution data
point (4 decimal characters) occupies one
memory location (2 bytes), whereas a high
resolution data point (5 decimal characters)
requires two memory locations (4 bytes). Table
1.5-1 shows the default allocation of memory
locations to Input, Intermediate, and the two Final
Storage areas. The *A Mode is used to
reallocate memory or erase Final Storage
(Section 1.5).
The default size of Final Storage is 64K bytes
or 29908 low resolution memory locations. One
RAM chip is dedicated to Final Storage. This
chip has 32K bytes. A minimum of 32K bytes
(16K memory locations) is ALWAYS retained in
Final Storage.
Final Storage can be divided into two parts:
Final Storage Area 1 and Final Storage Area 2.
Final Storage Area 1 is the default storage area
and the only one used if the operator does not
specifically allocate memory to Area 2. A
minimum of 768 memory locations will
ALWAYS be retained in Final Storage Area 1.
Two Final Storage Areas may be used to:
1. Output different data to different devices.
2. Separate archive data from real time display
data. In other words, you can record a short
time history of real time data and separately
record long term, archive data.
3. Record both high speed data (fast
recording interval) and slow data without
having the high speed data write over the
slow data.
Each Final Storage Area can be represented as
ring memory (Figure 2.1-1) on which the
newest data are written over the oldest data.
The Data Storage Pointer (DSP) is used to
determine where to store each new data point
in the Final Storage area. The DSP advances
to the next available memory location after
each new data point is stored.
FIGURE 2.1-1. Ring Memory Representation of Final Data Storage