Set Tag Controller

Navigation: Models ➔ Control Models ➔ Set Tag Controller

General Controller	PID Controller	Ratio / SetTag Controller

---

General Description

The Set Tag Controller model allows a user-defined or measured tag value to be transferred to one or more other tags. The input value may be transferred to the other tag(s) as follows:

Direct transfer (no manipulation of input value)	([math]\displaystyle{ y = x }[/math])
Multiplied by a ratio	([math]\displaystyle{ y = mx }[/math])
Multiplied by a ratio then offset	([math]\displaystyle{ y = mx+c }[/math])

Video Links

The following video is part of the Tutorial showing users how to use a Set Tag Controller:

• Add and Configure a Ratio Controller video

Similar Models

• General Controller - the user may carry out the same procedures using the General Controller and pgm code.

Examples

1. A Ratio, or Feed Forward Controller

The user needs to set a value, such as wash water to a filter as a ratio of the solids mass flow rate to the filter.

• Use the Measured Tag method;
• Select the Continuous set tag action;
• Copy the tag for the solids flow rate from the pipe feeding the filter into the Meas.Tag field;
• Use the Ratio calculation option and type in the required ratio value;
• Copy the tag for Required Feed for the wash water into the output tag.

The Set Tag Controller will continuously read the solids flow, multiply the value by the user defined ratio and set the wash water to the required flow.

2. Set Equipment Parameters in a number of Units at Start of a Run

The user has a number of units that have the same settings, e.g. thickener underflow solids in thickeners in a CCD circuit or heat exchanger area in heat exchangers in a Flash Train. In this case the user wishes to set a single parameter and transfer this to all similar units. This is only required when starting the model, as the parameter will not change during a run.

• Use the User Value method;
• Select the OnceOff As Required set tag action;
• Select either 'Set During Init' or 'Set After Init';
• Type in the required value into the User Value field;
• For the Calculation option select No Calculation;
• Type in the number of units that will be configured;
• Copy the required tags into the Output Tag fields.

The required parameter will be transferred to all units at the start of each run.

Please see the Demo Nickel Copper project for an example of this model in a SysCAD project.

Diagram

The diagram shows the default drawing of the Set Tag Controller unit.

Inputs and Outputs

There are no connections to this unit.

Data Sections

The default sections and variable names are described in detail in the following tables. The default Set Tag Controller access window consists of 3 sections:

1. SetTagControl tab - Contains general information relating to the unit. This also displays a table with a summary of each individual Controller.
2. TC1 tab - Each individual Controller will be displayed on a separate page. This page contains the information for each Controller.
3. Info tab - Contains general settings for the unit and allows the user to include documentation about the unit and create Hyperlinks to external documents.

Set Tag Controller Page

Unit Type: SetTagControl - The first tab page in the access window will have this name.

Tag (Long/Short)	Input / Calc	Description/Calculated Variables / Options
Tag	Display	This name tag may be modified with the change tag option.
Condition	Display	OK if no errors/warnings, otherwise lists errors/warnings.
ConditionCount	Display	The current number of errors/warnings. If condition is OK, returns 0.
GeneralDescription / GenDesc	Display	This is an automatically generated description for the unit. If the user has entered text in the 'EqpDesc' field on the Info tab (see below), this will be displayed here. If this field is blank, then SysCAD will display the UnitType or SubClass.
On	Tick Box	Enables or disables all of the Set Tag Blocks in the unit.
The following message and field is visible when upgrading the project with existing Set Tag Controllers from SysCAD 9.2 (or earlier) to SysCAD 9.3. Change numbering to start from 1 instead of 0. NB this affects Tags. Example: xxx.TC[0].Measure.Value becomes xxx.TC[1].Measure.Value
ChangeNumbering	Button	Update Numbering to Start from 1 instead of 0. Only visible if the Set Tag Controller was added in SysCAD 9.2 or earlier version. NB: this may affect external tag references such as reports, PGM, please adjust the external references appropriately if updating the controller numbering.
Count	Input	Allows the user to set the number of individual Set Tag control Blocks in this unit.
CheckAllTags	Button	This action will check all of the tags in the unit and display any errors.
SetAllTagsNow	Button	Only available if the inputs are User values. This action will set all of the output tags once.
Summary This shows a summary table with the following values for each individual Control block in the unit.
TC	Display	The Set Tag Control block number
On	Tickbox	The user may enable or disable each individual Set Tag Control block on the first page.
Meas / User	Display / Input	The measured value for each individual Set Tag Control block. If the block has a user value as the input, then this field will be White and the user may change the value here. If the input is a Measured Tag, then the field will be Grey and cannot be changed.
Out	Display	The output value for each individual Set Tag Control block.

TC1 Page

Each individual Control block will be displayed on a separate tab page. The blocks are numbered from 1, so the page labels will be TC1, TC2, etc.

Tag (Long/Short)	Input / Calc	Description/Calculated Variables / Options
Each Set Tag Block will have the following display fields.
On	Tick Box	Enables or disables this Set Tag Block.
Name	Input	The user may enter a name for the Set Tag block.
Index	Input	SetTag Control block Index. Useful for sorting the controllers in reports
Description	Input	The user may enter a description of the Set Tag block as text. This field is handled by SysCAD like a normal tag, therefore it can reported and set via Excel.
Options
Method	Measured Tag	The Input to the Set Tag block is a measured tag that is copied from another unit in the SysCAD model. This may change as the model solves, or it may be a constant value.
	User Value	The Input to the Set Tag block is set by the user or another unit in the model, such as a controller. This may change as the model solves, or it may be a constant value.
SetTagAction	Continuous	The output tag will be set at every iteration. This option is normally selected if this block acts as a feed forward controller.
	OnceOff As Required	The output tag will only be set at discrete times, when specified by the user. This option is normally selected if the block is used to set the parameters of a number of similar items of equipment at the start of a run. However, the user may set the tags at any time by clicking on the 'SetTagsNow' button.
SetAtStartup	Tick Box	If this is enabled then the output tag(s) will be set at startup, i.e. when the model is starting before the first iteration. Note: This field is only visible if OnceOff As Required is selected as the SetTagAction.
SetDuringInit	Tick Box	If this is enabled then the output tag(s) will be set during the Initialisation process, i.e. when the model is starting before the first iteration. Note: for builds prior to 138.28092, this field is only visible if OnceOff As Required is selected as the SetTagAction.
SetAfterInit	Tick Box	If this is enabled then the output tag(s) will be set during the first iteration after the Initialisation process. This field is only visible if OnceOff As Required is selected as the SetTagAction.
MatchCnvFromTag	Tick Box	If this is enabled then the conversion units of output tag(s) will always match the conversion units of the input tag. This field is only visible if Continuous is selected as the Set Tag Action. For example, if the measured tag is a mass flow, then the output tags will always be set to the same mass flow, t/h -> t/h, kg/h -> kg/h, etc.
TrackRangeLimit	Tick Box	If this option is disabled then the user will stop receiving warnings when the output value is at the OutMin or OutMax limits.
Buttons
CheckTags	Button	This action will check the tags in the block and display any errors.
SetTagsNow	Button	Only available if the input is a User value. This action will set the output tag(s) once.
Delete	Button	This allows the user to Delete the current individual Control block. Please note that there is no 'Undo'!
MoveUp	Button	This allows the user to increase the Priority of the current individual Control block. For example, if the current Control block is number 3, the user can change it to 2 or 1 by clicking on this button once or twice.
MoveDown	Button	This allows the user to decrease the Priority of the current individual Control block. For example, if there are 3 Control blocks in the unit and the current Control block is number 1, the user can change it to 2 or 3 by clicking on this button once or twice.
User.Value	Input	The required User value. This field is only visible if User Value is the Method selected. If MatchCnvFromTag tickbox is selected, the engineering units will become available.
Meas.Tag	Input	The Measured tag that is used in the block. This will be copied in from another unit in the model. This field is only visible if Measured Tag is the Method selected.
Output Values Current Values will be displayed if the Set Tag Action is Continuous and the fields will display the current values. Values at last Tag Set will be displayed if the Set Tag Action is OnceOff As Required and the fields will display the values when the output was last set.
Meas.Value	Display	Either the current measured value, or the measured values that was last set. This field is only visible if the Method selected is Measured Tag. If MatchCnvFromTag tickbox is selected, the engineering units will become available.
Output.Value	Display	Either the current output value or the value that was sent to the output tags when the Set Tag was last activated. If MatchCnvFromTag tickbox is selected, the engineering units will become available.
Calculation
CalcOption	No Calculation	The output tag(s) will be equal to the input tag, i.e. there is no manipulation of the input tag.
	Ratio	The input value will be multiplied by the ratio before setting the output tag(s).
	Ratio and Offset	The input value will be multiplied by the ratio and then the offset value will be added before setting the output tag(s).
Ratio	Input	The ratio value - the input value will be multiplied by this ratio before setting the output tag(s). This field is not visible if No Calculation is selected.
Offset	Input	The offset value - the input value will be multiplied by the ratio and then the Offset value will be added to the result before setting the output tag(s). This field is only visible if Ratio and Offset is selected.
OutMin	Input	The minimum output value. If MatchCnvFromTag tickbox is selected, the engineering units will become available.
OutMax	Input	The maximum output value. If MatchCnvFromTag tickbox is selected, the engineering units will become available.
Output Tags
TagCount	Input	The required number of Tags that must be set by the controller. The default is 1.
TagN	Input	Where N = 1, 2, 3, etc. The required tag that must be set by the controller. This tag will be copied in from the required unit. The number of fields available for tags is set by Tag Count.

Adding this Model to a Project

Add to Configuration File

Sort either by DLL or Group:

	DLL:	Control1.dll	→	Units/Links	→	Control: Set Tag Controller
or	Group:	General	→	Units/Links	→	Control: Set Tag Controller

See Model Selection for more information on adding models to the configuration file.

Insert into Project Flowsheet

Insert Unit

→

Control

→

Set Tag Controller

See Insert Unit for general information on inserting units.

Hints and Comments

1. If the CalcOption is "Ratio" or "Ratio and Offset", option MatchCnvFromTag is selected, and conversion family used is "Temperature" (T) then the ratio is always applied to the temperature value in Kelvin (regardless of the selected displayed units).