January 2016, Rev. 1
CAM216/16 IOM
Doc. Number: ECM-402-0116
30
Section 5: Detailed Setup and Options
Detailed Setup and Options
NOTE:
Calibration may be executed remotely by placing the selector switch in the REMOTE/AUTO
mode and commanding the actuator to close and then open and then close. The actuator will
automatically calibrate “Position Feedback” to the valve travel limits and make this information
available to the HART Interface. Both methods of calibration will move the actuator to
determine the end of travel points for the actuator. The actuator must move to each limit
of travel (fully open and fully close) or else the calibration will not be completed.
5.5
Function Type
The function type is defined by the parameter Function Type and defines the type or mode of
operation of the actuator. The two types allowed are BLOCK and MODULATING.
The Function Type – BLOCK is for on/off or Block type actuation of a valve. The Function Type –
MODULATING is for Positioner or Modulation type of valve actuation.
5.6
Actuator Command (On/Off)
The Actuator Command is only available when the actuator is configured for Block Mode (On/
Off). Actuator Command is used to command the actuator to the desired position of "Closed”,
"Opened" or "Stop”. If the actuator is commanded to its "Open" or "Closed" position, it will
remain in that position and will attempt to maintain that position except if something happens
to the actuator to cause the position to change, for instance if someone would try to move the
valve using the hand wheel. Once the actuator detects the position has changed, it will attempt
to move the actuator back to its commanded position. If the Hand wheel position is desired,
then the actuator must be placed in LOCAL/MANUAL.
If the actuator is given a "Stop" command, it will stop processing position data and will not
command the actuator to any position and will not adjust except the current position change
due to external influences. This command is used to manually position the actuator.
5.7
Setpoint (Positioner)
The Setpoint Command is only available when the actuator is configured for Modulating Mode
(Positioner). Setpoint is used to command the actuator to the desired position. The command
is represented as a percentage of the full travel of the device. The actuator will remain in the
commanded position (+/- Dead band) and will attempt to maintain that position except when
something happens to the actuator to cause the position to change. For instance, if someone
would try to move the valve using the Hand wheel, the position may change. Once the actuator
detects the position has changed, it will attempt to move the actuator back to its commanded
position. To move the actuator via another means, the actuator selector switch must be placed
in the Local/Manual or OFF position.
5.7.1 Dead band
An integral part of the Setpoint command is Dead band or Position Control Bandwidth.
Dead band is handled internally by the DCM and is a basic function of actuator internal
inertia, load inertia and the actuator motor starter. The Position Control Bandwidth
can be set in the DCM with value between 0.1% to 5.0%. Under most circumstances,
the actuator will require one of two options to use a Position Control Bandwidth less
than the default value of 1.0%. Both of these are additions to the electro-mechanical
reversing contactor.
