Control Mode; Characterization - Emerson Fisher FIELDVUE DVC6000 HW2 Instruction Manual

Instruction Manual
D103785X012

Control Mode

D Control Mode—Displays the current control mode of the instrument. This will show Analog if the instrument is in
Point­to­Point mode and is using a 4­20 mA signal for its power and set point. This will show Digital if the
instrument is in Multidrop mode and is using 24 VDC for power and a digital set point for control.
Note
Another mode, Test, may be displayed. Normally the instrument should not be in the Test mode. The digital valve controller
automatically switches to this mode whenever it needs to stroke the valve during calibration or stroke valve, for example.
However, if you abort from a procedure where the instrument is in the test mode, it may remain in this mode. To take the
instrument out of the Test mode, select Change Control Mode and enter Analog or Digital.
D Change Control Mode—Allows you to configure the control mode to Analog or Digital.
D Restart Control Mode—Defines the Control Mode of the instrument after a restart (e.g. power cycle). Available
choices are Resume Last, Analog and Digital.

Characterization

D Input Characterization
Input Characterization defines the relationship between the travel target and ranged set point. Ranged set point is the
input to the characterization function. If the zero power condition equals closed, then a set point of 0% corresponds to
a ranged input of 0%. If the zero power condition equals open, a set point of 0% corresponds to a ranged input of 100%.
Travel target is the output from the characterization function.
To select an input characterization, select Input Characterization from the Characterization menu. You can select from
the three fixed input characteristics shown in figure 3‐2 or you can select a custom characteristic. Figure 3‐2 shows the
relationship between the travel target and ranged set point for the fixed input characteristics, assuming the Zero
Power Condition is configured as closed.
You can specify 21 points on a custom characteristic curve. Each point defines a travel target, in % of ranged travel, for
a corresponding set point, in % of ranged set point. Set point values range from -6.25% to 106.25%. Before
modification, the custom characteristic is linear.
D Custom Characterization
To define a custom input character, select Custom Characterization from the Characterization menu. Select the point
you wish to define (1 to 21), then enter the desired set point value. Press Enter then enter the desired travel target for
the corresponding set point. When finished, select point 0 to return to the Characterization menu.
With input characterization you can modify the overall characteristic of the valve and instrument combination.
Selecting an equal percentage, quick opening, or custom (other than the default of linear) input characteristic
modifies the overall valve and instrument characteristic. However, if you select the linear input characteristic, the
overall valve and instrument characteristic is the characteristic of the valve, which is determined by the valve trim
(i.e., the plug or cage).
Configuration
June 2017
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