AnalogDevice Object

The AnalogDevice object can act as either a basic analog input device (with optional output) or as an analog regulator device that provides an external representation of a Proportional-Integral-Derivative (PID) controller that exists elsewhere, typically a Programmable Logic Controller (PLC) or a Distributed Control System (DCS).

Click one of the following Help topics to navigate to information about that topic.

Overview

The AnalogDevice object is an ApplicationObject that can be configured as either a basic analog device, or an analog regulator device. When configured as a basic analog device, the AnalogDevice object follows the traditional model of a basic analog input/output object with alarming and history. When configured as an analog regulator device, the AnalogDevice object provides an external model of a PID controller that exists in a field device, in addition to providing the traditional analog alarming and history capabilities.

For general information on objects, including relationships, deployment, and alarm distribution, see the Integrated Development Environment (IDE) documentation.

Topic Category	Topic Subcategory	Topic Details
Overview	AnalogDevice Object as a Basic Analog Input/Output Object
AnalogDevice Object as an Analog Regulator Object
Run-Time Behavior	State Changes
Continuous Execution - General
Continuous Execution - PV Alarms
Continuous Execution - Scaling
Continuous Execution - Advising Active Items
Continuous Execution - Time Propagation
Configuration	General Configuration
I/O Configuration
Alarms Configuration
History Configuration
Control Configuration
Run-Time Object Attributes	Alarm Aggregation Attributes
History Attributes
Alarm Attributes
Quality Handling

Topic Category	Topic Subcategory	Topic Details
Overview	AnalogDevice Object as a Basic Analog Input/Output Object
AnalogDevice Object as an Analog Regulator Object

For information on configuration options of object scripts, attributes, or features, click Attributes Help in the Help file header.

AnalogDevice Object as a Basic Analog Input/Output Object

When configured as a basic analog device, this object provides a means for reading and optionally writing analog signals from the field or from another object. The basic I/O characteristics are:

The AnalogDevice object supports alarming for PV conditions, such as when the PV:

In addition, you can configure the AnalogDevice object to allow or disallow the overriding of the PV value. If you enable the PV override, then you can use the PV.Mode attribute to place the AnalogDevice object into either Auto or Manual mode. When the AnalogDevice object is in Auto mode, the PV is updated from the field and matches the value and quality of the PVAuto attribute. When the AnalogDevice object is in Manual mode, the PVAuto attribute continues to be updated from the field, but the PV value does not. Instead, the PV can be set by a user write or a script, and the quality is always set to UNCERTAIN.

Finally, you can configure the AnalogDevice object to historize key variables, including PV and PV.Mode.

AnalogDevice Object as an Analog Regulator Object

When configured as an analog regulator device, the AnalogDevice object provides a means for reading and optionally writing two separate analog signals from the field or from another object: one PV value and one setpoint (SP) value. The basic I/O characteristics are:

The AnalogDevice object supports alarming for PV conditions, including when the PV:

Other controller-oriented features that can be configured for an AnalogDevice object of type analog regulator include:

Run-Time Behavior

State Changes

Once deployed and operating, AnalogDevice objects can assume one of several states:

Topic Category	Topic Subcategory	Topic Details
Run-Time Behavior	State Changes
Continuous Execution - General
Continuous Execution - PV Alarms
Continuous Execution - Scaling
Continuous Execution - Advising Active Items
Continuous Execution - Time Propagation


State Change	Behavior
Startup	None.
Going onscan	If the PV.Mode is set to Manual, then the PV is the last value, and the quality is UNCERTAIN. If the PV.Mode is set to Auto, then the PV is the Not-a-Number (NaN) value, and the quality is INITIALIZING. The NaN value is defined by the Institute of Electrical and Electronics Engineers, Inc. (IEEE). PV.Auto is set to NaN value, and the quality is INITIALIZING. If the object is an analog regulator, then the SP is the NaN value, and the quality is INITIALIZING. Any pending deviation alarm timer is reset. The time stamp of PV is set to the current time if the NaN value and INITIALIZING quality is set to PV. The time stamp stays unchanged if the value stays at the last value and no quality change.
Onscan	The object is active. For more information, see Continuous Execution - General, Continuous Execution - PV Alarms, and Continuous Execution - Scaling.
Going offscan	If the PV.Mode is set to Manual, then the PV is the last value, and the quality is UNCERTAIN. If the PV.Mode is set to Auto, then the PV is the NaN value, and the quality is BAD. If the object is an analog regulator, then the SP is the NaN value, and the quality is BAD. All alarm conditions become false and input values go to BAD quality. Any pending deviation alarm timer is reset. The time stamp of PV is set to the current time if the NaN value is set to PV, PVAuto, or SP. If the PV.Mode is set to Manual, then the time stamp stays unchanged if the value stays at the last value and quality is UNCERTAIN.
Offscan	The object is passive.
Shutdown	If references to the PV and/or SP attributes were registered and suspended at startup, these references are activated and unregistered.

Continuous Execution - General

If the AnalogDevice object is configured as a basic analog device with no output:

Continuous Execution - PV Alarms

Limit Alarms

Deviation Alarms

Rate-of-Change (ROC) Alarms

Rate-of-change alarms are used to detect and report a condition when the process value (PV) increases or decreases at too fast of a rate. You can specify a limit for both the increasing and decreasing directions. For the increasing limit, if the PV increases at a rate greater than the limit, an alarm is generated. Similarly, for the decreasing limit, if the PV decreases at a rate greater than the limit, an alarm is generated. The limit value in either case is a positive number.

In addition to specifying the rate limit value, the time dimension for the rate must be specified depending on the time dynamics of the variable being measured. The choices are per second, per minute, per hour, and per day. Finally, for calculation of the rate itself, the time interval at which the rate (or slope between points) is calculated is also specified as a time interval in milliseconds.

So, for example, if you want to put a rate limit on the rate at which a number of gallons accumulates in a tank as 200 gallons per minute, and you want to specify the calculation to be performed every 5 seconds, then specify:

Continuous Execution - Scaling

The time stamp of the resulting ScaledValue is the time stamp of the RawValue, if it has associated time stamp. Otherwise, the current time is used as the ScaledValue time stamp.

Continuous Execution - Advising Active Items

If you configure the object to have input or input/output and advisement of active items is enabled globally, both the reference count and suspend count for the PV and/or SP attribute is incremented when the object starts up. This puts the object into a suspended state and propagates a suspend message to the input source.

When the object is in a suspended state, no input scanning occurs, because no new input values are being sent by the input source. The quality of the suspended attribute is INITIALIZING.

Continuous Execution - Time Propagation

If the PV overide is disabled, the input's value, time, and quality (VTQ) is used to update PVAuto and PV.

If the PV overide is enabled and PV.Mode is Auto, the input's VTQ is used to update PVAuto and PV.

If the PV overide is enabled and PV.Mode is Manual, the input's VTQ is used to update PVAuto. PV stays at the last user set value, the current time of the set, and a quality of UNCERTAIN.

Configuration

The following table describe the object editor options for configuration and the associated attributes:

For general information on objects, including relationships, deployment, and alarm distribution, see the Integrated Development Environment (IDE) documentation.

Topic Category	Topic Subcategory	Topic Details
Configuration	General Configuration
I/O Configuration
Alarms Configuration
History Configuration
Control Configuration

For information on configuration options of object scripts, attributes, or features, click Attributes Help in the Help file header.

General Configuration

Use the General tab to configure general options for the AnalogDevice object.


Editor Option	Associated Attribute	Description	Run-Time Access (Supervisory, User, Read-Only, None)
Type	AnalogType	Used to specify whether the AnalogDevice object is a basic analog device or an analog PID regulator device. Valid values are: AnalogInput, AnalogRegulator.	Read-Only
Enable analog output	AnalogOutputEnabled	Used to allow the basic analog-type AnalogDevice object to have an output.	None
Enable PV override	PV.OverrideEnabled	Used to allow the PV mode to be set to Manual instead of the default of Auto.	Supervisory, User
Initial PV mode	PV.Mode	The initial PV mode setting, either Auto or Manual.	Supervisory, User
PV value	PV	The default "process value," in engineering units, if the initial PV mode setting is Manual. For extra quality handling, see Quality Handling.	Supervisory, User
Engineering units	PV.EngUnits	The name of the engineering units. For example, PSI. The maximum number of characters is 32.	User
PV deadband	Deadband	The value, in engineering units, by which the input must change to update the PVAuto value.	Supervisory, User
Enable I/O scaling	Scaled	Used to enable scaling between the raw value and the EU value.	None
Raw value - Minimum	RawMin	The raw input minimum to be used in the scaling calculation.	Supervisory, User
Raw value - Maximum	RawMax	The raw input maximum to be used in the scaling calculation.	Supervisory, User
EU value - Minimum	EngUnitsMin	The minimum value, in engineering units, used in the scaling calculation.	Supervisory, User
EU value - Maximum	EngUnitsMax	The maximum value, in engineering units, used in the scaling calculation.	Supervisory, User
EU range value - Minimum	EngUnitsRangeMin	If scaling is enabled, the lowest allowed value for PV before it is either clamped or set NaN, if clamping is enabled. This value must be less than or equal to the specified minimum engineering unit value.	Supervisory, User
EU range value - Minimum	EngUnitsRangeMax	If scaling is enabled, the highest allowed value for PV before it is either clamped or set NaN, if clamping is enabled. This value must be greater than or equal to the specified maximum engineering unit value.	Supervisory, User
Conversion mode	ConversionMode	Used to specify either Linear or Square Root for the equation that will be used to scale the input.	Read-Only
Clamp input to EU range	ClampEnabled	Used to allow the scaling process to clamp the engineering unit result. If clamping is enabled, the scaling calculation result is clamped at either the maximum engineering unit range value or the minimum engineering unit range value, and the PV quality is set to UNCERTAIN. If not clamped, and the PV exceeds the engineering unit range, then PVAuto is set to NaN, and the quality is set to BAD.	Supervisory, User

I/O Configuration

Use the I/O tab to configure input and output references for the AnalogDevice object.


Editor Option	Associated Attribute	Description	Run-Time Access (Supervisory, User, Read-Only, None)
PV input source	PV.Input.InputSource	The target source from which the value (plus quality) is to be read. Click the ellipse button to access the Attribute Browser.	Supervisory, User
Output destination differs from input source	AnalogOutput.DiffAddr	If enabled, the output destination can be configured to be different than the input source. This option only applies when the AnalogOutputEnabled attribute is set to TRUE and the analog type is basic AnalogInput.	None
PV output destination	PV.Output.OutputDest	The target location to which the output value will be written. Click the ellipse button to access the Attribute Browser.	Supervisory, User
SP reference	SP.Reference	The target destination to which the value will be written. This value also identifies the location from which PV is to be read if no other feedback source is specified. Click the ellipse button to access the Attribute Browser.	Supervisory, User
SP feedback address differs from SP output address	SP.SeparateFeedbackConfigured	If enabled, the SP feedback address will be sourced from a different address than the SP output. This option only applies when the analog type is AnalogRegulator.	None
SP feedback source	SP.ReferenceSecondary	The target location from which feedback is to be read, if different from the output location. Click the ellipse button to access the Attribute Browser.	Supervisory, User

Alarms Configuration

Use the Alarms tab to select the types of alarms to detect and the conditions under which alarms will be triggered.


Editor Option	Associated Attribute	Description	Run-Time Access (Supervisory, User, Read-Only, None)
Generate event upon PV change	PV.LogDataChangeEvent	If enabled, data change events for the PV will be logged to event history.	Supervisory, User
Detect PV level(limit) alarms	PV.LevelAlarmed	If enabled, alarms will be triggered for when the PV level reaches configured limits.	None
HiHi	HiHi.Alarmed	If enabled, an alarm will be triggered when the PV reaches the HiHi limit.	None
HiHi - Limit	HiHi.Limit	The HiHi limit that the PV must exceed to trigger an alarm.	Supervisory, User
HiHi - Priority	HiHi.Priority	See Alarm Attributes.	Supervisory, User
HiHi - Alarm Message Attribute	HiHi.DescAttrName	See Alarm Attributes. Click the ellipse button to access the Attribute Browser.	None
Hi	Hi.Alarmed	If enabled, an alarm will be triggered when the PV reaches the Hi limit.	None
Hi - Limit	Hi.Limit	The Hi limit that the PV must exceed before an alarm is triggered.	Supervisory, User
Hi - Priority	Hi.Priority	See Alarm Attributes.	Supervisory, User
Hi - Alarm Message Attribute	Hi.DescAttrName	See Alarm Attributes. Click the ellipse button to access the Attribute Browser.	None
Lo	Lo.Alarmed	If enabled, an alarm will be triggered when the PV reaches the Lo limit.	None
Lo - Limit	Lo.Limit	The Lo limit that the PV must exceed to trigger an alarm.	Supervisory, User
Lo - Priority	Lo.Priority	See Alarm Attributes.	Supervisory, User
Lo - Alarm Message Attribute	Lo.DescAttrName	See Alarm Attributes. Click the ellipse button to access the Attribute Browser.	None
LoLo	LoLo.Alarmed	If enabled, an alarm will be triggered when the PV reaches the LoLo limit.	None
LoLo - Limit	LoLo.Limit	The LoLo limit that the PV must exceed to trigger an alarm.	Supervisory, User
LoLo - Priority	LoLo.Priority	See Alarm Attributes.	Supervisory, User
LoLo - Alarm Message Attribute	LoLo.DescAttrName	See Alarm Attributes. Click the ellipse button to access the Attribute Browser.	None
Alarm deadband	LevelAlarm.ValueDeadband	The amount, in engineering units, that the PV must drop below either the HiHi limit or Hi limit, or increase above either the LoLo limit or Lo limit before an alarm is triggered.	Supervisory, User
Detect PV rate of change alarms	PV.ROCAlarmed	If enabled, alarms will be triggered for when the PV level reaches configured rates of change.	None
Up	PV.ROC.IncreasingHi.Alarmed	If enabled, an alarm will be triggered when the PV is increasing too fast.	None
Up - Limit	PV.ROC.IncreasingHi.Limit	The alarm limit that the rate of change calculation must exceed in order to trigger an alarm.	Supervisory, User
Up - Priority	PV.ROC.IncreasingHi.Priority	See Alarm Attributes.	Supervisory, User
Up - Alarm Message Attribute	PV.ROC.IncreasingHi.DescAttrName	See Alarm Attributes. Click the ellipse button to access the Attribute Browser.	None
Down	PV.ROC.DecreasingHi.Alarmed	If enabled, an alarm will be triggered when the PV is decreasing too fast.	None
Down - Limit	PV.ROC.DecreasingHi.Limit	The alarm limit that the rate of change calculation must exceed in order to trigger an alarm. (This value, although a positive value, actually indicates a negative rate of change, or a descending rate of change Hi limit.)	Supervisory, User
Down - Priority	PV.ROC.DecreasingHi.Priority	See Alarm Attributes.	Supervisory, User
Down - Alarm Message Attribute	PV.ROC.DecreasingHi.DescAttrName	See Alarm Attributes. Click the ellipse button to access the Attribute Browser.	None
Per	PV.ROC.Rate.Units	The units of time for the rate of change calculation.	Read-Only
Evaluate every	PV.ROC.EvalPeriod	The time interval, in milliseconds, at which the rate of change calculation and detection is performed.	Supervisory, User
Detect PV target deviation alarms	PV.DevAlarmed	If enabled, alarms will be triggered for when the PV level deviates from a target value by a configured amount.	None
Minor	PV.Dev.Minor.Alarmed	If enabled, an alarm will be triggered when the PV reaches the minor deviation tolerance.	None
Minor - Deviation	PV.Dev.Minor.Tolerance	The amount, in engineering units, that the PV must differ from the setpoint before an alarm will be triggered.	Supervisory, User
Minor - Priority	PV.Dev.Minor.Priority	See Alarm Attributes.	Supervisory, User
Minor - Alarm Message Attribute	PV.Dev.Minor.DescAttrName	See Alarm Attributes. Click the ellipse button to access the Attribute Browser.	None
Major	PV.Dev.Major.Alarmed	If enabled, an alarm will be triggered when the PV reaches the major deviation tolerance.	None
Major - Deviation	PV.Dev.Major.Tolerance	The amount, in engineering units, that the PV must differ from the setpoint before an alarm will be triggered.	Supervisory, User
Major - Priority	PV.Dev.Major.Priority	See Alarm Attributes.	Supervisory, User
Major - Alarm Message Attribute	PV.Dev.Major.DescAttrName	See Alarm Attributes. Click the ellipse button to access the Attribute Browser.	None
Setpoint	SP	The target value. The setpoint is only available for AnalogDevice objects configured as type AnalogRegulator (not Analog).	Supervisory, User
Deviation deadband	PV.Dev.Deadband	The amount the PV must drop (measured in engineering units) below any of the deviation limits before the respective condition is set to FALSE.	Supervisory, User
Settling period	PV.Dev.SettlingPeriod	The amount of time, in seconds, allowed for the PV to return within the normal range after the deviation alarm clears. (A deviation alarm cannot occur again until the alarm clears.) The value you specify will be converted to the following format: days hh:mm:ss.fffffff.	Supervisory, User
Bad PV	PV.Bad.Alarmed	If enabled, alarms will be triggered for when the PV has bad data values or data quality.	None
Bad PV priority	PV.Bad.Priority	See Alarm Attributes.	Supervisory, User
Alarm Message Attribute	PV.Bad.DescAttrName	See Alarm Attributes. Click the ellipse button to access the Attribute Browser.	None

History Configuration

Use the History tab to configure the historization of data values that are generated or received by the AnalogDevice object.


Editor Option	Associated Attribute	Description	Run-Time Access (Supervisory, User, Read-Only, None)
PV	PV.Historized	If enabled, the system historizes the default "process value," in engineering units, if the initial PV mode setting is Manual.	None
SP	SP.Historized	If enabled, the system will historize the target value.	None
PV mode	PV.Mode.Historized	If enabled, the system will historize the initial PV mode setting, either Auto or Manual.	None
Control mode	CtrlMode.Historized	If enabled, the system will historize the default value for the control mode, either Manual, Cascade, or None.	None
Control Track Flag	CtrlTrack.ValueHist.Historized	If enabled, the system will historize the current value of the control tracking flag.	None
Force storage period	<Attribute>.ForceStoragePeriod	See History Attributes.	Supervisory, User
Value deadband	<Attribute>.ValueDeadband	See History Attributes.	Supervisory, User
Trend high	<Attribute>.TrendHi	See History Attributes.	Supervisory, User
Trend low	<Attribute>.TrendLo	See History Attributes.	Supervisory, User
Interpolation Type	<Attribute>.InterpolationType	See History Attributes.	Supervisory, User
Sample Count	<Attribute>.SampleCount	See History Attributes.	Supervisory, User
Rollover Value	<Attribute>.RolloverValue	See History Attributes.	Supervisory, User
Enable Swinging Door	<Attribute>.EnableSwingingDoor	See History Attributes.	Supervisory, User
Rate DeadBand	<Attribute>.RateDeadBand	See History Attributes.	Supervisory, User

Control Configuration

Use the Control tab to specify control settings for an AnalogDevice object of type analog regulator.

Run-Time Object Attributes

Editor Option	Associated Attribute	Description	Run-Time Access (Supervisory, User, Read-Only, None)
SP high limit	SP.HiLimit	The Hi limit for SP writes.	Supervisory, User
SP low limit	SP.LoLimit	The Lo limit for SP user or supervisory writes.	Supervisory, User
Initial control mode	CtrlMode	The default value for the control mode, either Manual, Cascade, or None.	Supervisory, User
Control tracking enabled	CtrlTrack.Enabled	If enabled, control tracking will be allowed, and SP changes will be prohibited.	None
Control track input source	CtrlTrack.InputSource	The target source from which the CtrlTrack attribute value (plus quality) is to be read. Click the ellipse button to access the Attribute Browser.	Supervisory, User

Topic Category	Topic Subcategory	Topic Details
Run-Time Object Attributes	Alarm Aggregation Attributes
History Attributes
Alarm Attributes

Note Configurable run-time attributes are described in the configuration sections. For more information, see Configuration.

For a list of common attributes, click Attributes Help in the Help file header.


Attribute	Description	Run-Time Access (Supervisory, User, Read-Only, None)
CtrlTrack.DataType	The expected data type of the CtrlTrack attribute value. This is always Boolean.	Read-Only
CtrlTrack.ReadStatus	The cause of any errors that have occurred when data is read from the target feedback reference (object and attribute). This is the Message Exchange status and not the status of the communication to external systems or devices such as Programmable Logic Controllers (PLCs).	Read-Only
CtrlTrack.Value	The value that is read from the CtrlTrack.InputSource attribute.	Read-Only
CtrlTrack.ValueHist	The current value of the control tracking flag.	Read-Only
Hi.Condition	Set to TRUE if the PV has exceeded the Hi level limit.	Read-Only
HiHi.Condition	Set to TRUE if the PV has exceeded the HiHi level limit.	Read-Only
Lo.Condition	Set to TRUE if the PV has exceeded the Lo level limit.	Read-Only
LoLo.Condition	Set to TRUE if the PV has exceeded the LoLo level limit.	Read-Only
PV.Bad.Condition	If TRUE, then the calculated PV has a quality of BAD.	Read-Only
PV.Dev.Deviation	The current deviation, in engineering units, between the PV and the SP.	Read-Only
PV.Dev.Major.Condition	Set to TRUE when the difference between the PV and SP has exceeded the major tolerance and the timer has expired.	Read-Only
PV.Dev.Minor.Condition	Set to TRUE when the difference between the PV and the target has exceeded the minor tolerance and the timer has expired.	Read-Only
PV.Dev.TimeSinceTargetChange	The amount of time that has elapsed since the SP was changed. The format is: days hh:mm:ss.fffffff. The value is calculated based on the SPChangeTime attribute.	Read-Only
PV.Dev.SPChangeTime	The time of the most recent change to the SP value since object deployment. This time is used to calculate the TimeSinceTargetChange attribute.	Read-Only
PV.Input.DataType	The data type of the PV value. This is always Float.	Read-Only
PV.Input.ReadStatus	The cause of any errors that have occurred when data is read from the target feedback reference (object and attribute). This is the Message Exchange status and not the status of the communication to external systems or devices such as Programmable Logic Controllers (PLCs).	Read-Only
PV.Input.Value	The value that is read from the PV.Input.InputSource attribute.	Read-Only
PV.Output.DataType	The data type of the PV value. This is always Float.	Read-Only
PV.Output.WriteStatus	The cause of any errors when writing data to the target location (object and attribute), or, in the case where that location is in a DeviceIntegration Object, the actual field I/O status. This status is the Message Exchange status and, when OutputDest is a DeviceIntegration Object, the status of the communication to external systems or devices such as Programmable Logic Controllers (PLCs).	Supervisory
PV.Output.Value	A placeholder for values that will be written to the target location.	Read-Only
PV.ROC.DecreasingHi.Condition	Set to TRUE if the PV has exceeded the Lo rate of change limit.	Read-Only
PV.ROC.IncreasingHi.Condition	Set to TRUE if the PV has exceeded the Hi rate of change limit.	Read-Only
PV.ROC.Rate	The calculated rate of change of the PV.	Read-Only
PVAuto	This attribute is calculated independently of the state of the PVMode attribute. The PVAuto attribute is calculated as if the state of "PV" were always "Auto." The PVAuto attribute is calculated from the PV.Input.Value attribute using any configured scaling parameters. For extra quality handling, see Quality Handling.	Read-Only
SP.DataType	The data type of the SP value when the analog type is AnalogRegulator. This value is always Float.	Read-Only
SP.ReadStatus	The cause of any errors that have occurred when data is read from the target feedback reference (object and attribute). This is the Message Exchange status and not the status of the communication to external systems or devices such as Programmable Logic Controllers (PLCs).	Read-Only
SP.ReadValue	The value that is read from the SP.InputSource attribute when the analog type is AnalogRegulator. For extra quality handling, see Quality Handling.	Read-Only
SP.WriteStatus	Reports whether the last SP value written reached the intended target specified by the output destination. This only applies when the analog type is AnalogRegulator.	Supervisory
SP.WriteValue	The value received internally from this object or from an external Message Exchange client.	Supervisory, User

Alarm Aggregation Attributes

The following attributes are available for all Objects. If alarm aggregation is enabled on the Area, the following attributes aggregate their respective alarm status values for the Area, for all sub-Areas, contained objects, and their descendants assigned to the Area. If alarm aggregation is disabled, these attributes remain at their default values. Alarm aggregation attributes behave similarly to alarm aggregation of individual attributes.


Attribute	Description	Run-Time Access (Supervisory, User, Read-Only, None)
<Attribute>.AlarmCntsBySeverity	Array of counts of all alarms that are in UNACK_ALM, ACK_ALM, or UNACK_RTN states on the object, aggregated by severity levels 1-4.	Read-Only
<Attribute>.AlarmMostUrgentAcked	TRUE (default) indicates that no alarms are in the InAlarm state or waiting to be Acked. A value of TRUE also indicates that the most urgent alarm(s) on the object and its descendants in the InAlarm state have been acknowledged, whether or not they are currently InAlarm.	Read-Only
<Attribute>.AlarmMostUrgentIn Alarm	FALSE (default) indicates that no alarms are in the InAlarm state or waiting to be Acked. A value of FALSE indicates whether the most urgent alarm(s) on the object and its descendants are in the InAlarm state, whether or not they have been acknowledged.	Read-Only
<Attribute>.AlarmMostUrgentMode	The AlarmMode of the most urgent alarm(s) on this Object and its descendants. If no alarms are in the InAlarm state or waiting to be Acked, the value is the same as the AlarmMode for the Object.	Read-Only
<Attribute>.AlarmMostUrgent Severity	Severity level expressed as an integer 1-4 of the most urgent alarm(s) on the object and its descendants. If no alarm is in the InAlarm state or waiting to be Acked, the value is 0 (zero).	Read-Only
<Attribute>.AlarmMostUrgent Shelved	The Shelved status as a Boolean value for the “most urgent” alarm(s) on this Object and its descendants. A value of FALSE indicates that no alarms have been Shelved for the "most urgent" alarm(s) on this Object and its descendants.	Read-Only

History Attributes

If a historization Feature is enabled, then the following additional history-related attributes become available. None of these attributes can be alarmed.


Attributes	Description
<Attribute>.ForceStoragePeriod	The time interval, in milliseconds, at which the value must be stored, even if the value has not changed. A value of 0 disables this feature. As an example, a setting of 3600000 indicates the value must be stored once per hour (measured from the time the object was last put onscan). If this value is less than the scan period of the host object, forced storage will occur every scan period (effectively equivalent to setting a value deadband of 0).
<Attribute>.TrendHi	The default top of the trend scale for clients. This value must be greater than or equal to the low value for the trend. If this value is changed at run time, the maximum engineering unit change is not reflected in the historian until you redeploy the object. This attribute only applies to numeric data types.
<Attribute>.TrendLo	The default bottom of the trend scale for clients. This value must be less than or equal to the high value for the trend. If this value is changed at run time, the minimum engineering unit change is not reflected in the historian until you redeploy the object. This attribute only applies to numeric data types.
<Attribute>.ValueDeadBand	The amount in engineering units by which a value referenced by the attribute must change to force a storage. A value of 0 means it is unused, and thus any value change forces a storage. Also, a quality change in the attribute always forces a storage regardless of this setting. This attribute only applies to numeric data types.
<Attribute>.Description	The brief description for the attribute that is stored to history. You can use descriptive text or a reference to another string attribute containing the history description. If an attribute reference is used, it must be in the form: "me.AttrName". If you do not provide a description, the object description is used.
<Attribute>.InterpolationType	The method used by the Historian to interpolate analog historical data. The interpolation type determines which analog value is selected during a Historian data retrieval cycle. Interpolation types include System Default, Stairstep, or Linear. The default interpolation type is System Default. For Stairstep, the last known value is returned with the given cycle time. If no valid value can be found, a NULL is returned to the Historian. For Linear, Historian calculates a new value at the given cycle time by interpolating between the last known value prior to the cycle time and the first value after the cycle time. For System Default, the Wonderware Historian system-wide interpolation setting is used. The system-wide setting must be either stairstep or linear interpolated.
<Attribute>.SampleCount	Obsolete. Do not use.
<Attribute>.RolloverValue	A positive integer value that represents a tag’s reset limit when the Historian operates in counter retrieval mode. In counter retrieval mode the Historian uses a tag's rollover value to calculate and return the delta change between consecutive retrieval cycles. The default value is 0.0. The rollover value applies only to numeric attributes. The rollover value is disabled if the historical attribute data type is Boolean or a string.
<Attribute>.EnableSwingingDoor	Enables or disables the swinging door rate deadband. The default is disabled. The swinging door deadband is not applicable to Boolean or string data types. If you provide a valid swinging door rate deadband, the force storage period is now the deadband override period.
<Attribute>.RateDeadBand	The percentage rate of change deadband based on the change in the slope of incoming data values to the Historian. For example, specifying a swinging door rate deadband of 10 percent means that data is saved to the Historian if the percentage change in slope of consecutive data values exceeds 10 percent. The default is 0.0, which indicates a swinging door rate deadband is not applied. Any percentage greater than 0.0 can be assigned to the rate deadband.

Alarm Attributes

If an alarm attribute is enabled, then the following additional alarm attributes become available. None of these attributes can be alarmed.


Attribute	Description
<Attribute>.Acked	Used to specify whether an alarm has been acknowledged. This attribute is updated when the AckMsg attribute is set. This attribute is always set to FALSE when a new alarm condition is detected (when the InAlarm attribute changes from FALSE to TRUE).
<Attribute>.AckMsg	The operator comment at the time the alarm is acknowledged. Any received text is stored, and the Acked attribute is set to TRUE. Also, the TimeAlarmAcked attribute is set to the current time. The maximum length is 256 characters.
<Attribute>.AlarmMode	The current alarm mode setting. Valid values are: Enable, Disable, Silence.
<Attribute>.AlarmModeCmd	The command to set the alarm mode. Valid values are: Enable, Disable, Silence.
<Attribute>.Category	The category of the alarm. The label of each alarm category is fixed.
<Attribute>.DescAttrName	The description of the alarm. The description must be of type String or InternationalizedString, with a maximum length of 329 characters. The DescAttrName attribute can contain a static alarm description or a reference to another string attribute within the same object containing the alarm description. The reference must be in the form: "me.AttrName". If the reference is invalid, the actual reference string is used for the description. If nothing is supplied for the DescAttrName attribute, the object’s ShortDesc attribute is used at run time.
<Attribute>.InAlarm	The alarm state. This is exactly the same as the attribute in the host primitive that represents the alarm condition, except when the alarm state is disabled, in which case, InAlarm is set to Off, regardless of the actual condition state. The quality is set during execute to the quality of the attribute, except when the alarm is disabled, in which case the quality is always GOOD.
<Attribute>.Inhibit	If true, the alarm is disabled. This attribute is intended to be written to by a script, a user, or an input feature. Only the individual alarm is disabled. No other alarms are disabled in the same object or in any objects that are assigned to or contained by this object.
<Attribute>.Priority	The value for the urgency of the alarm. Valid values are 1 through 999, with 1 being the most urgent.
<Attribute>.TimeAlarmAcked	The timestamp indicating the last time this alarm was acknowledged. The date format reflects the current locale setting for the operating system.
<Attribute>.TimeAlarmOff	The timestamp indicating the last time this alarm (as represented by the InAlarm attribute) went off. The date format reflects the current locale setting for the operating system.
<Attribute>.TimeAlarmOn	The timestamp indicating the last time this alarm (as represented by the InAlarm attribute) went on. The date format reflects the current locale setting for the operating system.

Quality Handling

Attribute	Quality Handling
PV	When the PVMode is Manual, then quality is UNCERTAIN. When PVMode is Auto, the quality is the same as the PVAuto attribute quality.
PVAuto	The quality is BAD if the object is offscan. Otherwise, the quality is the same as the input quality, either INITIALIZING, UNCERTAIN, or GOOD. The quality can also be UNCERTAIN if the input quality is GOOD, but the value of PVAuto is less than the minimum scaled range or greater than the maximum scaled range.
SP	If the AnalogDevice object is configured as an analog regulator, when the object goes onscan, the quality set to INITIALIZING. While the object is executing, if external data cannot be translated to appropriate data type, the quality is set to BAD. Otherwise, the quality is set to the quality of the external data. When the object goes offscan, the quality is set to BAD.