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Function
Selections or
Prompt
Range of Setting
Lower Display
Upper Display
CONT ALG
PD+MR
(continued)
3PSTEP
TIMER
DISABLE
ENABLE
34
PD WITH MANUAL RESET is used whenever integral action is not
wanted for automatic control. The equation is computed with no
integral contribution. The MANUAL RESET, which is operator
adjustable, is then added to the present output to form the
controller output.
Switching between manual and automatic mode will be bumpless.
If you select PD with Manual Reset you can also configure the
following variations:
• PD (Two Mode) control,
• P (Single Mode) control.
Set Rate (D) to 0.
ATTENTION Other prompts affected: MAN RSET in the Tuning
Set Up group
THREE POSITION STEP—The Three Position Step Control
algorithm allows the control of a valve (or other actuator) with an
electric motor driven by two controller relay outputs; one to move
the motor upscale, the other downscale without a feedback
slidewire linked to the motor shaft. The deadband is adjustable in
the same manner as the duplex output algorithm.
The Three Position Step Control algorithm provides an output
display (OUT) which is an estimated motor position, since the
motor is not using any slidewire feedback. Although this output
indication is only an approximation, it is "corrected" each time the
controller drives the motor to one of its stops (0 % or 100 %). It
avoids all the control problems associated with the feedback
slidewire (wear, dirt, noise). When operating in this algorithm, the
estimated OUT display is shown to the nearest percent (i.e., no
decimal). This selection forces the Output Algorithm selection to
"POSITON".
Refer to the Operation section for motor position displays.
As a customer configurable option, when a second input board is
installed, the motor slidewire can be connected to the controller.
The actual slidewire position is then shown on the lower display as
POS. This value is used for display only. It is NOT used in the
Three Position Step algorithm. To configure this option, set Input
2 actuation to SLIDEW and then calibrate Input 2.
ATTENTION Other prompts affected: DEADBAND
TIMER allows you to enable or disable the timer option.
The timer option allows you to configure a timeout period and to
select timer start by either the keyboard (RUN/HOLD key) or Alarm
2. A digital input can also be configured to start the timer.
When the timer is enabled, it has exclusive control of the alarm 1
relay; any previous alarm configuration is ignored. At timeout, the
timer is ready to be re-activated by whatever action has been
configured. Alarm 1 is activated at the end of the timeout period.
UDC3200 Universal Digital Controller Operator Manual
Parameter Definition
04/08
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