Future Design MCTB 4.3, Руководство пользователя

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MCTB
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8.2.1 Calculating Log File Size
The MCTB saves the log file in a text-based format (.csv), so the amount of memory consumed for each reading
is dependent upon the number of digits required to accurately display the value (1 byte per character). This
optimizes memory usage but also makes calculating an exact file size difficult. To obtain a worst-case
approximation of the resultant file size, use the following formula:
File Size (Bytes) = (64 + LD) * number of readings in the file
Where:
LD (loop data) = 7 * number of points selected for logging
Example
MCTB with three loops of controller data (PV, SP, %Out selected) for each loop (total of nine points).
Logging set at one second interval running for a duration of one day.
LD: 7 * 9 = 63
number of readings in file: 60 secs/min * 60 mins/hr * 24 hrs/day = 86400
File Size (Bytes) = (64 + 63) * 86400 = 10,972,800
An MCTB logging nine points of data at a one second interval will consume a maximum of 11MB of memory
per day. With an SD memory card size of 8GB, the MCTB can log data for approximately two years before
the SD memory card is full.
8GB = 8,000MB (total memory card space) / 11MB (per day) = 727 days (1.9 years)
NOTE: Available memory space on the SD card is also affected by the number of ramp/soak programs, alarm
files and audit trail files that are stored. The quantity and size of these files will reduce the memory
space available for logging. Regular file maintenance is recommended in order to ensure adequate
space remains available for the logging of data.
8.3 Reviewing Historical Data
Historical files can be opened and viewed using the historical viewer. In order to view a historical data file, it
must first be opened by selecting
“Open” from the File menu. Once the file has been opened, the MCTB can
automatically plot the first eight channels of the historical data file or the user can choose to cancel the plot and
select which channels should be plotted as well as adjust the specific time period to plot.
NOTE: The open historical data file list will display up to 650 files. If more than 650 log files are present, the
files cannot be shown in the list and the files will have to be exported from the MCTB in order to view
them. This can be done either via USB file utilities (see section
8.4 USB File Transfer ) or FTP (see
section 8.5 FTP/FileWeb/DataWeb Interface ).
8.3.1 History Plot Setup
The history plot setup allows the user to select any time frame (zoom in/out) from the historical data file as well
as select up to six channels of data to plot.
To edit the settings for the historical plot, select “Set” from the Chart
menu.