DiscreteDevice Object

The DiscreteDevice object can be used to control and monitor discrete devices that have two or more states.

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Overview

Topic Category	Topic Subcategory	Topic Details
Overview	DiscreteDevice Object States
Monitoring a Discrete Device via Inputs
Controlling a Discrete Device via Outputs
Alarm Capabilities
Statistical Features
Run-Time Behavior	Continuous Execution - General	Advisement of Active Items
Time Propagation
Configuration	General Configuration
States Configuration
Inputs Configuration
Outputs Configuration
Alarms Configuration
Run-Time Object Attributes	Alarm Aggregation Attributes
History Attributes
Alarm Attributes
Quality Handling

Topic Category	Topic Subcategory	Topic Details
Overview	DiscreteDevice Object States
Monitoring a Discrete Device via Inputs
Controlling a Discrete Device via Outputs
Alarm Capabilities
Statistical Features

The DiscreteDevice object is a general purpose ApplicationObject that represents a large class of physical equipment common in manufacturing, such as pumps, valves, motors, and conveyors. These devices have two or more discrete physical states (for example, Open, Closed, and Moving). The actual state of a device is monitored via a combination of discrete inputs, and a device can be optionally controlled using a combination of discrete outputs. For more information on states, see DiscreteDevice Object States.

The state names are configurable and are mapped to both input and output Boolean combinations in truth-table form. The meaning of the states depends on the type of discrete device. For a pump, the states might be configured as "Off" and "On," while for a valve they might be configured as "Open," "Closed," and "Moving." Note that a control valve has a continuous position represented by an analog signal of 0 to 100% and is not properly represented with a discrete device. Control valves are best represented with the AnalogDevice object.

When a DiscreteDevice object is commanded to a new state, it sets the configured combination of discrete outputs for that state. When one or more of its monitored discrete inputs change, the DiscreteDevice object determines the new actual state of the equipment and sets the process value (PV) appropriately.

Input and output states are totally independent of each other and can be configured as required by your application; however, the input and output states can be linked by alarms. This allows the object to detect a command timeout and uncommanded change alarms when devices unexpectedly change, or fail to change when commanded to do so. For more information, see Alarm Capabilities.

Historization of key attributes including the current state (PV) and commanded state (Cmd) can also be configured.

Finally, the DiscreteDevice object supports a rich set of statistics reporting that you can enable during configuration. For more information, see Statistical Features.

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

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

DiscreteDevice Object States

The DiscreteDevice object has two key attributes that represent the current state (PV) and the commanded state (Cmd). Both of these are enumerations. The DiscreteDevice object can have up to five states that can be configured with state names that are appropriate to the equipment being monitored. The actual meanings of the states are dependent on the equipment:

Monitoring a Discrete Device via Inputs

If you configure the DiscreteDevice object to have inputs (feedback) from the field, the input values will be used to update the overall state of the device. A DiscreteDevice object can have up to four inputs. After defining the inputs, you will need to map the different input combinations to the possible states for the device.

For example, you might have a valve on your discrete device that can be either opened or closed. You have defined the passive state of the device as Closed, the first active state as Opened, and the fault state as Bad. You would then create references for two field inputs: one for the open position (Valve_Open), and one for the closed position (Valve_Close). You then would map the inputs to the defined states. For example:

By default, when the monitored discrete inputs change, the DiscreteDevice object determines the new actual state of the equipment and updates the value of the process value (PV) appropriately.

You can configure the DiscreteDevice object to allow or disallow overriding of the PV value. If you enable the PV override, then the object can be placed in Auto, Manual, or Simulate modes using the PVMode attribute.

Controlling a Discrete Device via Outputs

You can control (command) the passive, first active, and second active states of the discrete device via the Cmd attribute. The transition and fault states are not commandable. When a DiscreteDevice object is commanded to a new state, it sets an appropriate combination of discrete outputs for that state.

For example, you might map the first active state of "Open" to a discrete device output reference that will turn a valve to the open position. When you set the Cmd attribute to "Open," the valve will be "commanded" to be opened. If inputs (feedback) are configured for the DiscreteDevice object, the object could then detect when the valve is actually open or closed.

Commanding a discrete device to a new state does not directly change the PV unless you have the PVMode set to "Simulate."

Alarm Capabilities

The DiscreteDevice object provides sophisticated alarming capabilities, including:

Statistical Features

The DiscreteDevice object offers advanced built-in state tracking calculations that can be used for equipment monitoring and time-in-use tracking, including:

Run-Time Behavior

Run-time behavior pertains to the running state of a deployed DiscreteDevice object. Once deployed and operating, DiscreteDevice objects can assume one of the following states:

Continuous Execution - General

Advisement of 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 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.

Time Propagation

If the PV mode is Manual, the PV keeps the last value, time stamp, and UNCERTAIN quality, regardless of any PVAuto and input changes.

If the PV mode is Auto and there is only one input specified, the PV, PVAuto, and state attributes are computed based on the input value. The input time stamp is used to update the time stamp of PV, PVAuto, and the state attributes.

If the PV mode is Auto and more than one input is specified, the PV, PVAuto, and state attributes are computed based on the input values. The time of the computation is used to update the time stamp of PV, PVAuto, and the state attributes.

If the CtrlMode is Manual, Cmd has changed, and the output receives a new value based on the result of calculation, then the current time is also set to the output.

An explicit time set request to Cmd does not change the Cmd’s value, time, or quality (VTQ). No calculation is performed and no new VTQ is set to the output values.

If the object changes any attribute value and quality, the current time is used to update the attribute's time stamp.

Configuration

The following sections 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.

Valve_Open	Valve_Close	Mapped State
0	0	Bad
0	1	Closed
1	0	Opened
1	1	Bad

Topic Category	Topic Subcategory	Topic Details
Run-Time Behavior	Continuous Execution - General	Advisement of Active Items
Time Propagation

State Change	Behavior
Startup	All statistics are reset.
Going onscan	If the PVMode is set to Manual, then the PV is the last value, and the quality is UNCERTAIN. If the PVMode is set to Auto, then the PV is the Fault state, and the quality is INITIALIZING. PVAuto is set to the Fault value, and the quality is INITIALIZING. The time stamps for PVAuto, PV, and other calculated attributes are updated to the current time if their value or quality changes because of a scan state change.
Running onscan	See Continuous Execution - General on page 123.
Going offscan	If the PVMode is set to Manual, then the PV is the last value, and the quality is UNCERTAIN. If the PVMode is set to Auto, then the PV is the Fault state, and the quality is BAD. PVAuto is set to BAD quality, Fault value. All alarm conditions become false and input values go to BAD quality. Any command timeout alarm timer that is pending is reset. The time stamps for PVAuto, PV, and other calculated attributes are updated to the current time if their value or quality changes because of a scan state change.
Offscan	The object is passive.
Shutdown	If a reference to PV was registered and suspended at startup, that reference is activated and unregistered.

Topic Category	Topic Subcategory	Topic Details
Configuration	General Configuration
States Configuration
Inputs Configuration
Outputs Configuration
Alarms 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 specify whether the device has feedback (has inputs), can receive commands (has outputs), or both.


Editor Option	Associated Attribute	Description	Run-Time Access (Supervisory, User, Read-Only, None)
Enable inputs	HasFeedback	If enabled, this discrete device can have feedback (input) from the field.	None
Historize PV	PV.Historized	If enabled, the PV value will be historized.	None
Force storage period	PV.ForceStoragePeriod	See History Attributes.	Supervisory, User
SampleCount	PV.SampleCount	See History Attributes.	Supervisory, User
Generate event upon PV change	PV.LogDataChangeEvent	If enabled, data change events for the PV will be logged to event history.	Supervisory, User
Enable outputs	HasCmd	If enabled, the discrete device can be commanded to change state.	None
Historize command	Cmd.Historized	If enabled, command changes will be historized.	None
Force storage period	Cmd.ForceStoragePeriod	See History Attributes.	Supervisory, User
SampleCount	Cmd.SampleCount	See History Attributes.	Supervisory, User
Enable statistics	Stats.Enabled	Used to enable statistics. You can only enable statistics if the object has been configured to have feedback. Statistics provide useful process information calculations on the discrete device being monitored, such as duty cycles and time running utilizations. Statistics also allow you to monitor equipment usage.	None

States Configuration

Use the States tab to specify the name of each state for the DiscreteDevice object.


Editor Option	Associated Attribute	Description	Run-Time Access (Supervisory, User, Read-Only, None)
Enable second active state	EnableStateActive2	If enabled, a second active state is allowed. Second active states typically will exist for devices such as reversible motors. If you unlock this option, the following options will also be unlocked: The Active2 option on the Outputs tab. For more information, see Outputs Configuration. The Input to PV Map option on the Inputs tab. For more information, see Inputs Configuration. If you lock the following options, this option will also be locked: The Input to PV Map option on the Inputs tab. For more information, see Inputs Configuration. The Active2 option on the Outputs tab. For more information, see Outputs Configuration.	Read-Only
Enable transition state	EnableStateInTransition	If enabled, a transition state is allowed. A transition state typically will exist for devices such as dual-input solenoid valves. If you unlock this option, the Input to PV Map option on the Inputs tab will also be unlocked. For more information, see Inputs Configuration. If you lock the Input to PV Map option on the Inputs tab, this option will also be locked. For more information, see Inputs Configuration.	Read-Only
Passive state	StateNames[1]	The name of the passive state.	Read-Only
First Active state	StateNames[2]	The name of the first active state.	Read-Only
Second Active state	StateNames[3]	The name of the second active state.	Read-Only
Transition state	StateNames[4]	The name of the transition state.	Read-Only
Fault state	StateNames[5]	The name of the fault state.	Read-Only

Inputs Configuration

Use the Inputs tab to configure the inputs that will determine the monitored state of the DiscreteDevice object. Options on this tab are only available when the This object has inputs check box is selected on the General tab.


Editor Option	Associated Attribute	Description	Run-Time Access (Supervisory, User, Read-Only, None)
Number of Inputs	InputCnt	The number of inputs for this object. A default input name appears for each input. The maximum number of inputs allowed is four. If you unlock this option, the Input Name and Input to PV Map options will also be unlocked. If you lock the Input Name and Input to PV Map options, this option will also be locked.	Read-Only
Input Name (Input 1 - Input 4)	InputNames[1-4]	The name assigned to the input reference. The name cannot include spaces or special characters, such as $, #, :, and _. If you lock this option, the Number of Inputs will also be locked. If you unlock the Number of Inputs option, this option will also be unlocked.	Read-Only
Input Source Reference (Input 1 - Input 4)	[Input Name].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
Input to PV Map	FieldInputToPVMap[1-16]	An array that is used to specify how to calculate PVAuto for each valid combination of input values. The lowest order bit is Input1. The length of the array depends on the number of inputs. States that are not applicable are not included in this array. All elements should be set to a non-Null value. If you lock this option, the following options will also be locked: The Number of Inputs option. The Enable second active state and Enable transition state options on the States tab. For more information, see States Configuration. If the following options are unlocked, this option will also be unlocked: The Number of Inputs option. The Enable second active state and Enable transition state options on the States tab. For more information, see States Configuration.	User
Allow manual or simulate PV modes	PVOverrideEnabled	If enabled, the PV mode can be set to Manual or Simulate instead of the default of Auto. In Auto mode, the PV will be calculated internally based on the inputs.	User
Initial PV mode	PVMode	The PV mode override setting, either "Manual," "Auto," or "Simulate." If PVMode is Manual, the PV can be set by an external operator (user) write. If PVMode is Auto, the PV will be calculated internally based on the inputs. If PVMode is Simulate, the PV takes the value of the Cmd attribute (after the command timeout alarm limit) and the quality is set to UNCERTAIN. The Simulate mode is only available if the object has outputs.	Supervisory, User

Outputs Configuration

Use the Outputs tab to configure the outputs that will be controlled by the commanded state of the DiscreteDevice object. Options on this tab are only available if the This object has outputs check box is selected on the General tab.


Editor Option	Associated Attribute	Description	Run-Time Access (Supervisory, User, Read-Only, None)
Number of outputs	OutputCnt	The number of outputs for this object. A default output name appears for each output. The maximum number of outputs allowed is six. If you unlock this option, the Output Name, Passive, Active1, and Active2 options will also be unlocked. If you lock the Output Name, Passive, Active1, and Active2 options, this option will also be locked.	Read-Only
Output Name (Output 1 - Output 6)	OutputNames[1-6]	The name assigned to the output reference. The name cannot include spaces or special characters, such as $, #, :, and _. If you lock this option, the Number of outputs option will also be locked. If you unlock the Number of outputs option, this option will also be unlocked.	Read-Only
Output Destination Reference (Output 1 - Output 6)	[Output Name].OutputDest	The target location (address) from which the output value will be obtained. Click the ellipse button to access the Attribute Browser. If you create a reference to "me" for the output destination reference, you must have inputs enabled, or else the reference will not resolve.	Supervisory, User
Passive (Output 1 - Output 6)	PassiveStateOutputs[1-6]	Used to enable outputs for the passive state. If you lock this option, then the Number of outputs option will be locked. If you unlock the Number of outputs option, this option will also be unlocked.	User
Active1 (Output 1 - Output 6)	Active1StateOutputs[1-6]	Used to enable outputs for the first active state. If you lock this option, then the Number of outputs option will also be locked. If you unlock the Number of outputs option, this option will also be unlocked.	User
Active2 (Output 1 - Output 6)	Active2StateOutputs[1-6]	Used to enable outputs for the second active state. If you lock this option, the following options will also be locked: The Number of outputs option. The Enable second active state option on the States tab. For more information, see States Configuration. The Active2 commandable state can only be locked if the Active2 state is enabled on the States tab. If you unlock following options, the Active2 option will also be unlocked: The Number of outputs option. The Enable second active state option on the States tab. For more information, see States Configuration.	User
Initial control mode	CtrlMode	Used to specify whether an operator (user) or other objects (supervisory) can set the value of the Cmd attribute. Valid values are "Manual" and "Cascade." In Manual mode, the object can be written to by an operator, but not by other objects. In Cascade mode, the object can be written to by other objects, but not by an operator.	Supervisory, User
Control tracking enabled	CtrlTrack.Enabled	If enabled, the commandable state of the device will continually reflect the value of PV. Normally, the Cmd attribute is externally set by users or other objects (depending on the control mode). However, if control tracking is enabled, then the value of the Cmd attribute takes the value of the PV, regardless of the control mode. The output is NULL if control tracking and PV are not in a commandable state.	None
Control track input source	CtrlTrack.InputSource	The reference to an external Boolean flag for control tracking. You can configure the object such that a PLC notifies the object that the PLC is in control of the state of the actual physical device and is no longer accepting commands. If configured in this way, the commandable state reflects the value of PV. Click the ellipse button to access the Attribute Browser.	Supervisory, User

Alarms Configuration

Use the Alarms tab to enable alarming for the different states of the DiscreteDevice object.


Editor Option	Associated Attribute	Description	Run-Time Access (Supervisory, User, Read-Only, None)
Detect uncommanded change alarm	UncommandedChangeAlarm.Alarmed	If enabled, an alarm will be triggered when the PV changes from the currently commanded state to any other state. This alarm cannot be detected without feedbacks, so if the object does not have feedbacks, then you cannot enable this alarm.	None
Priority	UncommandedChangeAlarm.Priority	See Alarm Attributes.	Supervisory, User
Alarm message attribute	UncommandedChangeAlarm.DescAttrName	See Alarm Attributes. Click the ellipse button to access the Attribute Browser.	None
Detect command timeout alarm	CmdTimeoutAlarm.Alarmed	If enabled, an alarm will be triggered when a command causes the PV to change within the timeout period.	None
Priority	CmdTimeoutAlarm.Priority	See Alarm Attributes.	Supervisory, User
Limit	CmdTimeoutAlarm.Limit	The maximum amount of time allowed for the value of the PV to match the command value before an alarm is generated, if alarming is enabled. The value you specify will be converted to the following format: days hh:mm:ss.fffffff.	Supervisory, User
Alarm message attribute	CmdTimeoutAlarm.DescAttrName	See Alarm Attributes. Click the ellipse button to access the Attribute Browser.	None
Report the first active state as an alarm	PV.IsActive1.Alarmed	If enabled, an alarm will be triggered when the first active state occurs.	None
Priority	PV.IsActive1.Priority	See Alarm Attributes.	Supervisory, User
Alarm message attribute	PV.IsActive1.DescAttrName	See Alarm Attributes. Click the ellipse button to access the Attribute Browser.	None
Report the second active state as an alarm	PV.IsActive2.Alarmed	If enabled, an alarm will be triggered when the second active state occurs.	None
Priority	PV.IsActive2.Priority	See Alarm Attributes.	Supervisory, User
Alarm message attribute	PV.IsActive2.DescAttrName	See Alarm Attributes. Click the ellipse button to access the Attribute Browser.	None
Report the fault state as an alarm	PV.IsNull.Alarmed	If enabled, an alarm will be triggered when the fault state occurs.	None
Priority	PV.IsNull.Priority	See Alarm Attributes.	Supervisory, User
Alarm message attribute	PV.IsNull.DescAttrName	See Alarm Attributes. Click the ellipse button to access the Attribute Browser.	None
Report the first active state duration alarm	Stats.Active1DurationAlarm.Alarmed	If enabled, an alarm will be triggered if the object is in the first active state longer than the duration limit.	None
Priority	Stats.Active1DurationAlarm.Priority	See Alarm Attributes.	Supervisory, User
Limit	Stats.Active1DurationAlarm.Limit	The duration that the object can remain in the first active state (since the last statistics reset) before an alarm is generated, if alarming is enabled. This value can only be cleared by a statistics reset. The value you specify will be converted to the following format: days hh:mm:ss.fffffff.	Supervisory, User
Alarm message attribute	Stats.Active1DurationAlarm.DescAttrName	See Alarm Attributes. Click the ellipse button to access the Attribute Browser.	None
Report the second active state duration alarm	Stats.Active2DurationAlarm.Alarmed	If enabled, an alarm will be triggered if the object is in the second active state longer than the duration limit.	None
Priority	Stats.Active2DurationAlarm.Priority	See Alarm Attributes.	Supervisory, User
Limit	Stats.Active2DurationAlarm.Limit	The duration that the object can remain in the second active state (since the last statistics reset) before an alarm is generated, if alarming is enabled. This value can only be cleared by a statistics reset. The value you specify will be converted to the following format: days hh:mm:ss.fffffff.	Supervisory, User
Alarm message attribute	Stats.Active2DurationAlarm.DescAttrName	See Alarm Attributes. Click the ellipse button to access the Attribute Browser.	None

Run-Time Object Attributes

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)
Cmd	The commanded state of the DiscreteDevice object. This value can be any of the defined state names for the passive, first active, or second active states. If CtrlMode is Manual, Cmd can be written to by an operator (user). If CtrlMode is Cascade, Cmd can be written by other objects (supervisory). Any valid external set to Cmd results in the associated state outputs being written out during the next execute. Before being stored to Wonderware Historian history, the value is converted to an integer, where 1 = Passive state, 2 = Active1 state, 3 = Active2 state, 4 = Transition state, and 5 = Fault state.	Supervisory, User
CmdTimeoutAlarm.Condition	Set to TRUE when both: The PV is greater than or less than the Cmd value. The current value of the internal command timer is greater than the time specified by the command timeout alarm limit. (The command timer starts when the Cmd value is externally set and differs from the PV.) This attribute is not available if there are no inputs, the command timeout alarm limit is set to 0, control tracking is enabled, or the PVMode is set to Simulate.	Read-Only
CtrlTrack.Datatype	The data type for the control tracking input.	Read-Only
CtrlTrack.ReadStatus	The current calculated read status for control tracking input.	Read-Only
CtrlTrack.Value	The current value for the control tracking Boolean flag.	Read-Only
PV	The monitored state of the DiscreteDevice object. By default, PV is internally calculated (transferred from PVAuto) based on the values of the inputs. If PVMode is Manual, the value of PV can be externally written to by operators (users). If PVMode is Simulate, the value is copied from the Cmd value. Before being stored to Wonderware Historian history, the value is converted to an integer, where 1 = Passive state, 2 = Active1 state, 3 = Active2 state, 4 = Transition state, and 5 = Fault state. For extra quality information, see Quality Handling.	Supervisory, User
PV.IsActive1	If TRUE, the PV is in the first active state. For extra quality information, see Quality Handling.	Read-Only
PV.IsActive2	If TRUE, the PV is in the second active state. For extra quality information, see Quality Handling.	Read-Only
PV.IsInTransition	If TRUE, the PV is in the transition state.	Read-Only
PV.IsNull	If TRUE, the PV is NULL, and the quality of PV is not INITIALIZING.	Read-Only
PV.IsPassive	If TRUE, the PV is in the passive state.	Read-Only
PVAuto	The monitored state of the DiscreteDevice object. This value is internally calculated based on the values of the inputs. For extra quality information, see Quality Handling.	Read-Only
Stats.Active1Cnt	The number of transitions of the PV into the first active state since the last statistics reset.	Read-Only
Stats.Active1DurationAlarm.Condition	Set to TRUE if the total amount of time that the PV is in the first active state exceeds the duration alarm limit.	Read-Only
Stats.Active1DurationLast	The most recent duration that the PV was in the first active state. The format is: days hh:mm:ss.fffffff.	Read-Only
Stats.Active1DurationTotal	The total amount of time that the PV was in the first active state since the last statistics reset. The format is: days hh:mm:ss.fffffff.	Read-Only
Stats.Active2Cnt	The number of transitions of the PV into the second active state since the last statistics reset.	Read-Only
Stats.Active2DurationAlarm.Condition	Set to TRUE if the total amount of time that the PV is in the second active state exceeds the duration alarm limit.	Read-Only
Stats.Active2DurationLast	The most recent duration that the PV was in the second active state. The format is days hh:mm:ss.fffffff.	Read-Only
Stats.Active2DurationTotal	The total amount of time that the PV was in the second active state since the last statistics reset. The format is: days hh:mm:ss.fffffff.	Read-Only
Stats.ElapsedTime	The amount of time since the last statistics reset. This time includes the amount of time that the object is offscan. The format is: days hh:mm:ss.fffffff.	Read-Only
Stats.LastReset	The time of the last statistics reset.	Read-Only
Stats.PassiveCnt	The number of transitions of the PV into the passive state since the last statistics reset.	Read-Only
Stats.PassiveDurationLast	The most recent duration that the PV was in the passive state. The format is: days hh:mm:ss.fffffff.	Read-Only
Stats.PassiveDurationTotal	The total amount of time that the PV was in the passive state since the last statistics reset. The format is: days hh:mm:ss.fffffff.	Read-Only
Stats.Reset	Used to reset all statistical counters.	Supervisory, User
UncommandedChangeAlarm.Condition	Set to TRUE when the PV changes from the currently commanded state to any other state and the quality of PV is GOOD or UNCERTAIN (not BAD). This attribute is not available if there are no feedbacks, control tracking is enabled, or the PVMode is set to Simulate.	Read-Only

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.

History Attributes

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

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


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.

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

Attributes that have extra quality values (other than GOOD) are listed in the following table:

Attribute	Quality Description
PV	When PVMode is set to Simulate or Manual, the quality is UNCERTAIN. When PVMode is Auto, the quality value is the same for the PVAuto quality value.
PVAuto	Set to BAD if the object is offscan or if any input value has BAD quality. If any input quality is INITIALIZING, set to INITIALIZING. If any input quality is UNCERTAIN, set to UNCERTAIN. Otherwise, quality is set to GOOD.
PV.IsActive1 PV.IsActive2	Each of these attributes has a calculated quality value, which will always be the same as the quality of PV.