Specifications

OPERATIONS
Page 81 MRC-565 Packet Data Radio Operations & Maintenance
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5.8.2 Acquire Mode:
There are three modes used by the radios for controlling data acquisition from the CR1000.
These are "ALL", "CURRENT", and "LAST,N".
The CR1000,ACQMODE,ALL mode will read all the data records in each Table, starting from
the last location pointers set into the radio. This is useful where all the data for each site must be
transmitted, not just the most-recent data. This mode lets the CR1000 gather data independently
and lets the radio acquire and transmit the data as the MB RF Link permits. For example, the
user might want the CR1000 to store data every hour, but have the radio acquire and transmit all
of it at midnight, or have the radio acquire and transmit data as soon as possible. For each scan of
final storage the radio will read as many data reports from each Table in the CR1000 as it can.
The command CR1000, MAXQ, NN sets the maximum number of data reports to be acquired
per scan. These limits are discussed below in the memory management paragraph.
The CR1000,ACQMODE,CURRENT mode will acquire and transmit only the last or most
recent data record in each Table for every scan of the CR1000’s final storage.
The CR1000,ACQMODE,LAST,N mode will read the last "n" data records from each Table
each scan of the CR1000’s final storage. This mode is useful when you want to be able to change
the reporting interval remotely, and the CR1000 program cannot be modified. For example, you
can setup the CR1000 program to record data every minute, but have the radio acquire the most
recent data every hour. You can then change the radios acquisition scan timing to any interval
from one minute to 24 hours without modifying the CR1000 program.
5.8.3 Data Retrieval Pointer Initialization
The normal data collection method is to set the pointers to the last or most-recent data record,
then let the radio collect and transmit data whenever new data has been recorded into the
CR1000 final storage. The pointers will also be set to the most recent data report if the radio
resets. Power failures and subsequent recovery will leave the pointers where they were at the
time of the failure and continue from that point in a 545B, but will be lost in a 565 radio.
The radio maintains an internal pointer for accessing each data Table in the CR1000. These
pointers are accessed each time the radio requests data from the CR1000. The CR1000 records
each data Table in a “circular ring buffer” and will reuse memory locations when the Table gets
full. The size of each Table can be displayed using the CR1000 command. The size value uses
the field name MAXRECORDS. It should be noted that the pointers increment from 0 -
4,294,967,294 but the “circular ring buffer” MAXRECORDS limit is a much smaller number.
Any time stamps prior to the oldest, or beyond the newest of the actual records stored will not be
valid.
The CR1000, STAT will display the start, current, end and time stamps pointers for each Table.