The following table describes the attributes used by the Sideloop PI Staged Output module.
Make sure the Process ID and Process Units attributes are set according to the needs of your system. If the Process ID selected is Airflow, Airflow Diff, or Other, the you must set the Process Range as necessary. The Process Range must be greater than zero. If Process ID is Other, the user should configure the Time Constant and Process Dead Time attributes from the details view of the PID Pre-Processor logic block inside the module’s logic view. See the PID Pre-Processor logic block description and the Process ID Configuration Restrictions in the Control topic of the Logic section for details.
|
Name |
Type 1 |
Description |
Default Value |
|---|---|---|---|
|
Sideloop PI Staged Output Attributes Common Attributes |
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|
Control Status |
V |
Current status of the module. |
Set Name: Control Status |
|
Direct Acting |
Signals the action of the PID: True = Direct Acting, False = Reverse Acting. Direct acting control is used in applications where an increase in the process variable causes the controller’s present value to increase. An example of direct acting control is temperature control with a cooling coil. With reverse acting control, an increase in the process variable causes the control present value to decrease. Temperature control with a heating coil, flow rate control, or static pressure control applications are three examples of reverse acting control. |
True |
|
|
Max Capacity Fraction |
Contains the ratio of the largest stage to the sum of all the stages. |
1.0 |
|
|
Mode |
Allows the state to be set to Off, Max, or Control. |
Control Set Name: Off/Max/Control |
|
|
Output Overridden |
Indicates when the actual output controlled by this output is overridden by a user. |
False |
|
|
Output Position |
Provides the current Present Value of the output that this controller drives. |
0% |
|
|
PID Tuning Reset |
Causes the PID objects to reset their tuning parameters to the default based on the appropriate Process ID. |
Normal Set Name: PID Tuning Reset |
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|
Process ID |
Allows the user to specify the process being controlled. |
DA-T Set Name: Process ID |
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|
Process Range |
Magnitude of the range that the PID Process Variable traverses as the PID Present Value varies between its minimum and maximum values. User does not need to configure this parameter unless Process ID = Airflow or Airflow Diff. In these cases, Process Range should be configured to the design maximum flow rate of the controlled device. For other Process ID values, the effective process range is determined automatically from the standards table. |
22 °C, 40 °F |
|
|
Process Units |
Specifies the units for the PID. |
°C, °F Set Name: Unit |
|
|
Process Variable |
Specifies that when Mode is commanded to Control, this is the variable that is controlled and must therefore respond to changes in the output. For example, it can be connected to the Zone Temperature. |
22 °C, 72 °F |
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|
SL-ABSEFFORT (SL Absolute EWMA Effort) |
Provides an EWMA based on the absolute value of (Current Present Value - Last Present Value). The PID computes this value. |
0.0 Display Units: % |
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|
SL-ABSERROR (SL Absolute EWMA Error) |
Provides an EWMA based on the absolute value of (Setpoint - Process Variable). The PID computes this value. |
0.0 Display Units: °C, °F |
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|
SL-ERROR (SL EWMA Error) |
Provides an EWMA based on the difference of (Setpoint - Process Variable). The PID computes this value. |
0.0 Display Units: °C, °F |
|
|
SL-EWMA (SL EWMA Present Value) |
Provides an EWMA of the Present Value. The PID computes this value. |
0.0 Display Units: % |
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|
SL-MINOFF (Minimum Off Time) |
Minimum off duration for all stages. |
120 Seconds |
|
|
SL-MINON (Minimum On Time) |
Minimum on duration for all stages. |
120 Seconds |
|
|
SL-OUTSTATE (State) |
G, V |
Current State of the module |
Set Name: Off/Max/Control |
|
SL-SP (Setpoint) |
Desired setpoint for the process variable to be controlled to when commanded to Control. |
22 °C, 72 °F |
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|
Attributes That Must be Connected to the MSC XX Controller |
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Control Band |
V |
Control band for the MSC. |
Display Units: °C, °F |
|
Eff Minimum Off Time |
V |
Contains the minimum off time used by the MSC. |
Display Units: Seconds |
|
Eff Minimum On Time |
V |
Contains the minimum on time used by the MSC. |
Display Units: Seconds |
|
Eff Process Time Const |
V |
Contains the effective process time constant used by the MSC. |
Display Units: Seconds |
|
Eff Process Variable |
V |
Contains the Process Variable used by the MSC. It is filtered when the Process Time Constant is shorter than the sum of the Minimum On Time and Minimum Off Time. |
Display Units: °C, °F |
|
Instant Shutdown |
V |
Indicates to the MSC to shut off all outputs instantly. |
False |
|
PMAC Period |
V |
Specifies the period of time used by the PMAC algorithm portion of the MSC. |
Display Units: Seconds |
|
SL-O (Percent Cmd) |
V |
Controls the single actuator that is providing cooling or heating. |
Display Units: % |