Loop Attributes - Metasys - LIT-1201793 - Software Application - Site Management Portal - 12.0.50

Metasys Site Management Portal Help

Brand
Metasys
Product name
Site Management Portal
Document type
User Guide
Document number
LIT-1201793
Version
12.0.50
Revision date
2023-06-02
Language
English

This object contains attributes common to many Metasys system objects. These common attributes are described in the Common Object Attributes section. This section includes attributes of the Focus/Configuration tab, the Diagnostics tab (if applicable), and any other tab specific only to this object. See the Object and Feature Tabs section for information on the attributes that appear on the other tabs of this object (for example, the Hardware and Options tab appear on point objects).

Note: In the Notes column, letters for the attributes indicate the following: C - Configurable, N - Value Not Required, W - Writable.
Table 1. Loop Attributes - Focus/Configuration Tab

Attribute Name

Notes

Values/Options/Range

Description

Action

C,W

Direct

Reverse

Indicates whether the loop is direct or reverse acting.

Alarm State

 

Uses BACEventState set.

Indicates whether the object has an active alarm state associated with it. The intrinsic alarming algorithm determines the Alarm State value.

Bias

   

Indicates the bias value used by the loop algorithm. If the Bias Reference does not contain a value, a read of the Bias attribute returns an Unknown Property error.

Bias Reference 1

C,N,W

 

Provides the object reference for the Bias attribute. The Loop object reads and signs up for changes in the Present Value attribute of the object referenced by the Bias Reference. The value received is stored as the Bias.

Controlled Var Variable

 

Restricted to field mapper points.

Reflects the Present Value of the field point mapper defined by the Controlled Variable Reference.

Controlled Variable Reference 2

C,W

  Defines the field point mapper that represents the source of the input to the control loop.

COV Increment

    Defines the minimum change in the Present Value required for the object to report a change to other feature objects.

Derivative Constant

   

Indicates the value of the derivative gain parameter used by the loop algorithm. If the Derivative Constant Reference does not contain a value, a read of the Derivative Constant attribute returns an Unknown Property error.

Derivative Constant Reference1

C,N,W

 

Provides the object reference for the Derivative Constant attribute. The Loop object reads and signs up for changes in the Present Value attribute of the object referenced by the Derivative Constant Reference. The value received is stored as the Derivative Constant.

Display Precision

C,W

Uses Display Precision set.

Indicates the rounded position and the number of decimal places to display for this object.

Integral Constant

   

Indicates the value of the integral gain parameter used by the loop algorithm. If the Integral Constant Reference does not contain a value, a read of the Integral Constant attribute returns an Unknown Property error.

Integral Constant Reference1

C,N,W

 

Provides the object reference for the Integral Constant attribute. The Loop object reads and signs up for changes in the Present Value attribute of the object referenced by the Integral Constant Reference. The value received is stored as the Integral Constant.

JCI Out of Service Reference

C,W

 

Provides the object reference for the JCI Out of Service attribute. The Loop object reads and signs up for changes in the Present Value attribute of the object referenced by the JCI Out of Service Reference. The reference must be a BI, BO, or BV object. When the state of the JCI Out of ServiceReference is True, the PID loop algorithm is placed out of service.

JCI Out of Service Value Reference

C,W

 

Provides the object reference for the JCI Out of Service Value Reference attribute. The Loop object reads and signs up for changes in the Present Value attribute of the object referenced by the JCI Out of Service ValueReference. The reference must be an AI, AO, or AV object. When the Loop object is out of service, its Present Value assumes the value of this referenced object.

Manipulated Variable Reference2

C,W

Restricted to field points.

Defines the field point mapper that represents the destination of the output of the control loop.

Manual Tuning

C

False

Controls whether the gain values of the PID Loop object can be changed. These values include Proportional Constant, Derivative Constant, Integral Constant, Bias, Maximum Output, and Minimum Output. When the value of this attribute is False, these referenced values cannot be changed.

Max Output

   

Indicates the maximum value of the output (Present Value) as limited by the PID loop algorithm. This value is normally used to prevent the algorithm from controlling beyond the range of the controlled device, and to prevent integral term wind up. If the Maximum Output Reference does not contain a value, a read of the Max Output attribute returns an Unknown Property error.

Maximum Output Reference1

C,N,W

 

Provides the object reference for the Max Output attribute. The Loop object reads and signs up for changes in the Present Value attribute of the object referenced by the Maximum Output Reference. The value received is stored as the Max Output.

Min Output

   

Indicates the minimum value of the output (Present Value) as limited by the PID loop algorithm. This value is normally used to prevent the algorithm from controlling beyond the range of the controlled device, and to prevent integral term wind up. If the Minimum Output Reference does not contain a value, a read of the Min Output attribute returns an Unknown Property error.

Minimum Output Reference1

C,N,W

 

Provides the object reference for the Min Output attribute. The Loop object reads and signs up for changes in the Present Value attribute of the object referenced by the Minimum Output Reference. The value received is stored as the Min Output.

Present Value

    Indicates the current output value of the loop algorithm.

Present Value Reference

C,W

Restricted to field points.

Provides the object reference for the Present Value attribute. The Loop object reads and signs up for changes in the Present Value attribute of the object referenced by the Present Value Reference. The value received is stored as the Present Value.

Proportional Const

   

Indicates the value of the proportional gain parameter used by the loop algorithm. If the Proportional Constant Reference does not contain a value, a read of the Proportional Const attribute returns an Unknown Property error.

Proportional Constant Reference1

C,N,W

 

Provides the object reference for the Proportional Const attribute. The Loop object reads and signs up for changes in the Present Value attribute of the object referenced by the Proportional Constant Reference. The value received is stored as the Proportional Const.

Reliability

 

Uses Reliability set.

Reflects the Reliability attribute of the object referenced by the Present Value Reference attribute, providing an indication of whether the Present Value of the loop in question is reliable. This attribute may have a value of Reliable or Open when the field point mapper’s Reliability is Reliable or Open. This attribute may have a value of Unreliable when the field point mapper’s Reliability is a value other than Reliable or Open.

Setpoint

    Reflects the Present Value of the field point mapper defined by the Setpoint Variable Reference.

Setpoint Variable Reference2

C,W

  Defines the field point mapper that represents the setpoint for the control loop.

Units

 

Uses Units set.

Reflects the Units attribute of the object referenced by the Present Value Reference attribute.

Update Interval

 

Units = milliseconds

Indicates the time period, in milliseconds, between updates to the Present Value attribute.
1 You may optionally configure a reference for this BACnet optional property. If you do not define the optional reference for some reason, the Loop object responds to a read for the corresponding value with an Unknown Property error.
2 You must configure references to this BACnet required property to successfully create the Loop object. This reference appears red in the wizard until configured.