Trend Data Storage - Emerson Vilter Vission 20/20 Operation And Service Manual

Section 15 • Trend Chart
zoom level operator can view 3 minutes of trend data
and Zoom In button will be inactive. At minimum
zoom level operator can view full 120 hours of trend
data and Zoom Out button will be inactive.
Back/Forward:
• These buttons allow the operator to move the plot
and view trend data at different time intervals.
• Forward button will be inactive when the operator
is viewing the fi rst data point plotted on the screen
(i.e. when time interval is displaying 0:00). Back but-
ton will be inactive when the operator is viewing the
last data point on the screen (i.e. when time interval
is displaying 120:00). At minimum zoom level, Back
& Forward buttons will be inactive.
Trace:
• This button allows the operator to move a white cur-
sor line across all four trend lines and receive a read-
out of all four variables at that point in time. When the
Trace button is pressed, cursor position is displayed
along with value of all four variables on the screen.
Hold:
• This button allows the operator to stop the data from
advancing on the display without stopping the trend
feature. When the Hold button in pressed, Hold Time
is displayed on the screen.
Trace Back( < ) / Forward ( > ):
• These buttons allow the operator to move a white
cursor line across trend lines and view trend data
value at that point. These buttons will only be active
when Trace button is pressed. When these buttons
are pressed, cursor is moved and trace position is up-
dated on the screen.
Setup:
• This button allows operator to open the Trend Setup
screen. This button is inactive when the trend feature
is running.
15 – 2

Trend Data Storage

The trend analysis screen shows recorded data for prob-
lem analysis or tuning improvements. A logging buffer
holds 5 minutes of data sampled at 10 second intervals.
When the logging buffer fi lls with 5 minutes of data, it
is automatically transferred to a temp csv fi le. A temp
trend fi le will hold up to 1MB of accumulated data.
When the temp fi le has accumulated 1MB of data, data
from temp fi le is written to new trend fi le and temp fi le
is overwritten with new data in logging buffer till next
1MB of data. When a total of 15MB of trend data is accu-
mulated, and the logging buffer has fi lled with another
5 minutes of data to write, the fi le with the oldest trend
data is deleted.
Vission 20/20 • Operation and Service Manual •Vilter/Emerson • 35391SC 1.9