17 – 2
Section 17 • Trend Chart
MicroVission Controller • Operation and Service Manual • Emerson • 35391MV 1.3
Back/Forward
These buttons allow the Operator to move the plot and
view trend data at different time intervals.
The forward button will be inactive when the Operator
is viewing the rst data point plotted on the screen (i.e.
when the displayed time interval is 0:00). The back but-
ton will be inactive when the operator is viewing the last
data point on the screen (i.e. when the displayed time in-
terval is 120:00). At minimum zoom level, both the Back
& Forward buttons will be inactive.
Trace
This button allows the Operator to move a white cursor
line across all four trend lines and receive a read out of all
four variables at that point in time. When the Trace but-
ton is pressed, the cursor position is displayed along with
the values of all four variables on the screen.
Hold
This button allows the Operator to stop the data from
advancing on the screen, without stopping the trend
feature itself. When the Hold button is pressed, the Hold
Time is displayed on the screen.
Trace Back (<) / Forward (>)
These buttons allow the operator to move a white cur-
sor line across the trend lines, and to view the trend data
values at that point. These buttons will only be active
when the trace button has been pressed. Using these
buttons will move the cursor, and the trace position will
be updated on the screen.
Setup
This button allows the operator to open the Trend Setup
screen. This button is inactive when the trend feature is
running.
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 lls up with 5 minutes of data,
it is automatically transferred to a temporary .csv le. A
temp trend le will hold up to 1MB of accumulated data.
When the temp le reaches this 1MB limit, the data is
written to new trend le, and the temp le is overwrit-
ten with new data from the logging buffer until reaching
again 1MB of data.
When a total of 15MB of trend data has been accumu-
lated, and the logging buffer has lled with another 5
minutes of data to write, the le with the oldest trend
data is deleted.
NOTE
Trend data will be stored with either temperature or
pressure units depending on the selected Process
Control Mode.