Instruction Manual

Calibration
September 2013
5-3
Travel Calibration
There are two procedures available for calibrating
travel:
 Auto Calibration
 Manual Calibration
Auto Calibration (1-3-1-1)
User interaction is only required with Auto Calibration
when the feedback connection is SStem - Standard
(Sliding Stem - Standard). A feedback connection of
Rotary - All, SStem - Roller (Sliding Stem - Roller)
requires no user interaction and you can start with
step 6.
For a SStem - Standard feedback connection,
interaction provides a more accurate crossover
adjustment. Setting crossover establishes the zero
degree point for the geometric correction used to
translate the rotary motion observed by the travel
sensor into the linear motion of the sliding-stem valve.
When a double-acting actuator is used, you will be
prompted to run the Relay Adjustment when Auto
Calibration is selected. Select Yes to adjust the relay.
Select No to proceed with Auto Calibration. For
additional information, refer to Relay Adjustment in this
section.
Select Auto Calibration from the Calibrate menu, then
follow the prompts on the Field Communicator display
to automatically calibrate travel.
1. Select the method of crossover adjustment:
manual, last value, or default. Manual is the
recommended choice. If you select Manual, the Field
Communicator will prompt you to adjust the crossover
in step 3.
If you select Last Value, the crossover setting
currently stored in the instrument is used and there
are no further user interactions with the
auto-calibration routine (go to step 6). Use this
selection if you cannot use manual, such as when you
cannot see the valve.
If you select Default, an approximate value for the
crossover is written to the instrument and there are no
further user interactions with the auto-calibration
routine (go to step 6). Use this selection only as a last
resort. Default assumes a midrange position on the
travel sensor as the crossover point, however, this
may not be an appropriate value to use for crossover
because of variations in mounting and travel sensor
calibration.
2. The instrument seeks the high and low drive points
and the minor loop feedback (MLFB) and output bias.
Figure 5-1. Crossover Point
ACTUATOR
STEM
FEEDBACK ARM
90_
A6536−3 / IL
No user interaction is required in this step. For a
description of these actions see step 6.
3. If you select Manual in step 1, you are asked to
select an adjustment source, either analog or digital. If
you use a current source to adjust the crossover,
select Analog and go to step 4. If you wish to adjust
the current source digitally, select Digital and go to
step 5.
Note
The analog option is not available
when the DVC6000 SIS is operated by
0-24 VDC in multi-drop mode.
4. If you selected Analog as the crossover adjustment
source, the Field Communicator prompts you to adjust
the current source until the feedback arm is 90° to the
actuator stem, as shown in figure 5-1. After you have
made the adjustment, press OK and go to step 6.
5. If you selected Digital as the crossover adjustment
source, the Field Communicator displays a menu to
allow you to adjust the crossover.
Select the direction and size of change required to set
the feedback arm so it is 90° to the actuator stem, as
shown in figure 5-1. Selecting large, medium, and
small adjustments to the crossover causes changes of
5