16(19)
Setpoint
is the current value of the AUTO mode setpoint,
written by the control system or entered by user.
POS_D
displays the limit information that is either copied
from the limit switches or calculated from the position sen-
sor.
The page Output is presented in figure 19.
Figure 19. Page Output.
Output Value
is the AO block output value. This value is
user writable only in manual mode.
Positioning value
is the final valve position control (servo
control) setpoint. The possible difference between this
value and Output is due to signal modifications, such as
characterization, dead angle compensation, cutoff and lim-
iting.
3.3.2 Device Status
The device status window reports the device revision num-
bers, serial numbers and active warnings and alarms.
The Device status window is presented in figure 20.
Figure 20. Device status window.
3.3.3 Valve Diagnostics
3.3.3.1 Trends
Trends are continuously saved in the device memory.
Trends show the previous 30 full days, 12 full months, and
up to 25 full years. In addition, trends show a
Now
value,
which is the average value of the previous 0-24 hours. Fig-
ure 21 shows a sample trend.
Trend selector
parameter is used to select the trend that
is shown in the pages "Last 30 days", "Last 12 months" and
"Last 25 years".
Trends status
displays the status of the current trend
reading procedure.
Figure 21. A sample trend graph
3.3.3.1.1 Time Axis
