Siemens SITRANS VP300, Руководство по эксплуатации

Страница: 123 / 190

Operate
6.2 Parameter description
SITRANS VP300 with or without HART
Operating Instructions, 03/2011, A5E01258666-03
121
"3.7.2 Trends"
Use of trends
Trends show the process related to a variable in the past. A trend always consists of 20
values, which represent the average value of the variable for the observed time periods.
Depending on the selected trend, the 20 values represent a time period of:
● 30 minutes
● 8 hours
● 5 days
● 2 months
● 30 months
Note
Trend period is too short
If less than 20 values are available for a trend, because the measurement period was not
long enough, the incomplete trend curve is drawn right-aligned. That is, no curve is drawn
from the lower limit to the time for which the first measured value is available.
If no value is available at all, the display shows "No measured values available".
The following trends can be selected:
● Position
● Deviation of control
● Stiction
● Lower endstop
● Upper endstop
● Temperature
● Deadband