Tidal Engineering Synergy Compact, Техническое руководство

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Synergy Controller Technical Manual, Revision H
Page 65
Synergy Controller Data Logging Capacity Calculations
As described above, the Synergy Controller records process data, setpoints and machine diagnostics to its
Storage Card. This information can be exported at a later time to a USB Hard Disk or to the FTP server and
used in a test report or for system troubleshooting as explained in the previous section. Calculations below
estimate the Synergy Controller's logging capacity; i.e. the number of history samples that can be recorded
on the Storage Card.
The number of samples depends on the number of bytes available on the internal Storage Card and the
amount of data that is logged per sample.
SCINFO can be used to determine the number of bytes available on the Storage Card thru the TCP/IP, RS-
232 or IEEE communications interface.
Command Format: ? SCINFO.
Response example: “Total: 8128512 Free: 1048576”
To determine the amount of data that is logged, use the following table and formulas. The table below lists
the information that can be logged. Each data type requires a specific amount of storage space on the
Storage Card. In addition, there are a number of overhead bytes per sample for time and other
housekeeping data.
For example, assume that we want to record CH1 Actual (Temperature) and CH2 Actual (Humidity)
readings.
Capacity can be calculated as follows:
Samples=X/(Y+Z
1
+Z
2
+Z
3
)
Where:
X=2 MBytes available on Storage Card (Available Storage Card capacity)
Y=21 Bytes (Number of bytes of overhead per sample)
Z
n
=(Number of bytes required for n samples)
Thus, the number of samples that can be stored are calculated:
Samples=X/(Y+Z
1
+Z
2
)
Samples= 2,097,152/(21+6+6)
Samples=63,550
If we record 60 samples per hour we will have the capacity to record for 1,059 hours.
Hours = Samples/Sample Rate
Hours = 63,550/60
Hours = 1,059
The actual time may be less than this since other data stored on the machine including profiles will reduce
the number of available bytes. In addition, existing data stored in the history file will reduce the number of
samples that can be saved. Other data recorded in the file are alarm events and header information saved
when the Synergy Controller is restarted.