Eval tags - configuration dialog box

Editing of all objects in the process D2000 CNF is being performed in the configuration dialog box, a specific part of which is common for all editable objects and another part depends on the type of edited object.

Configuration dialog box of eval tags consists of several parts (tabs) that contain similar parameters.

General properties
Process alarms

General properties


A text string describing the eval tag. Maximum: 128 characters.
Possibility to use the Dictionary (to open press CTRL+L).

Status Text

Defines a status text for the eval tag. Status text allows to redefine values' identifications of the eval tag.

Transformation palette

Selection of an index to transformation palette. See the topic Transformation palette.

Value type

Value type selection of the eval tag. Admissible value types are listed in the following table.

IdentificationEval tag value type
DeLogical value
CeInteger value
AeAnalog value
TmAAbsolute Time
TmRTime interval - relative time

Technical units

Technical units of the eval tag. Maximum: 12 characters. Possibility to use the Dictionary (to open press CTRL+L).


Technological limits may be defined for eval tags of the Ce - integer, Ae - analog and TmR - time interval type. There are four limits: VHL, HL, LL and VLL. Limit may be specified either directly - by entering a value into the input field, or its value may be defined by a system object (dynamic limit) - the button placed right from the input field.

VHLVery High Limit - the highest limit
HLHigh Limit - high limit
LLLow Limit - low limit
VLLVery Low Limit - the lowest limit

Values of individual limits determine the state of the eval tag according to the value. The relation eval tag value - limits gives 6 possible states.

LimitObject state according to relation  Value- Limit
 Above VHL (object value > VHL)
 Above HL (HL < object value < VHL)
 Normal (LL < object value < HL)
 Bellow LL (VLL < object value < LL)
 Bellow VLL (object value < VLL)

As the limits can be dynamic (determined by the object value), a situation may occur, when the condition VLL<LL<HL<VHL is not met (the limits crossing). The eval tag is then in the state Limit Problem.

Process alarms

Configuration dialog box of Eval tags - Process alatms tab


Time delay (in seconds) for the evaluation of process alarm. Process alarm is raised, if a cause of raising the alarm is valid at least within this period.

Block alarms

Enabled Block Alarm option blocks the evaluation of process alarms.

Ignore invalid

If the option is checked, it will remove invalid values when evaluating one of defined process alarm.

Example: value change from S1 to S2 is executed as follows: S1 --> invalid --> S2.
If the parameter is checked, the alarm evaluation will be: S1--> S2.
If the parameter is not checked, the alarm evaluation will be: S1 --> invalid --> S2.

Mask for NoAlarm

Selection of a display mask, that will be used in process D2000 HI (the Alarm list - the Event description column) after changing the status of one of the defined process alarms into the Normal state.

Individual items allowing the settings of parameters of process alarms are ordered in a table. The table contains the following columns:


Raise signal parameter contains three checkboxes with the following function:

Generating the signal means, that the system tag Signal_Trigger is set to TRUE value.



The arithmetical expression that determines the eval tag value. The expression may contain the extended syntax, may be written in several lines, and may contain a comment. Comment begins the character ';' and finish at the line end. For example:

M.1 + ; description

Note: Typing the character '^' after the name of an object of Structured variable shows the list of all structure columns.

For more information on expressions see the chapter Mathematical expressions in eval tags and events.

Replace Invalid values with 0

If checked, all invalid values of the objects defined in the expression will be replaced with the value of 0. The feature can be used to prevent the expression from getting invalid value.

There are converted just the values of input objects, invalid values of intermediate data are not converted. Values of inputs objects are converted as follows:

Other value types are not converted.


Buttons to select an object of D2000 system. Selected object is inserted into the expression on the current cursor position.


Buttons to select a constant. Clicking it, opens the dialog box containing the list of predefined constant. Selected constant is inserted into the expression in the current cursor position.


Buttons to select a function. Clicking it, opens the List of functions dialog box. Selected function is to be inserted into the expression at the current cursor position.


Buttons to select an attribute. Clicking it, opens the dialog box containing the list of attributes. Selected attribute is inserted into the expression at the current cursor position.

Start value

Value of the object before beginning the calculation. Maximum: 20 characters.

Start value checkout

Start value is saved in a text form. During the system start, Server assigns values to individual objects according to the start value definition. In case of the successful conversion of a start value (text) to the required type, a value of the eval tag will be valid. If the conversion is not successful, then this value will be invalid. It is possible to save a start value that cannot be converted to the required type. The button Start value checkout () checks the start value and, in case of unsuccessful conversion, reports it.

Target column

If no target column is defined, the value of the expression (the input field Expression) will become the value of an eval tag. If is defined, it must contain the reference to a column of an object of Structured variable type in form: ObjectName[0]^ColumnName. This notation defines a structured variable column, which will contain the results of the expression evaluated.

If a constant expression of value 1 is defined, the process D2000 Calc (admistrator of objects of Eval tag) type ) ensures that all fields of a defined column will have the same value of 1.

If there is an expression Sec+1, the process D2000 Calc (admistrator of objects of Eval tag) type ) ensures that all fields of a defined column will have the same value, which corresponds to the value of system variable Sec increased by 1.

A reasonable use of this option is the possibility to use a reference to a column of a structured variable in an expression, where in brackets (row index) is a value of 0. Such reference will be reffered to as a reference to a column of a structured variable. This ensures that when evaluating an expression, the value of which is inserted into e.g. 3rd row, all the indeces with the constant value of 0 will be replaced with the value of 3.

Structured variable SV.Production consists of 10 rows and 3 columns.

Column Type Meaning
ProductsALL Int Number of products
Rejects Int Number of rejects
ProductsOK Int Number of good-quality products

Obviously the following equation can be formed:
ProductsOK = ProductsALL - Rejects

Provided that the columns ProductsALL and Rejects are populated fully automatically and the value of the column ProductsOK is to be determined, it can be done with the configuration of an eval tag as described below:
SV.Production[0]^ProductsALL - SV.Production[0]^Rejects

Calculation of the difference will be in the column SV.Production[0]^ProductsOK.
Note: The expression may contain references to columns of other structured variables.

Evaluation method

Selection of a method used to calculate the expression determining the eval tag value. Available evaluation methods:

Evaluation period


Expression evaluation period (hour:min:sec). It is defined only for the periodical evaluation method of an eval tag.


Time offset of the basic time interval (hour:min:sec). It is defined only for the periodical evaluation method of the eval tag.

Use monotonic time


Maximum density of evaluation [s]

The parameter can be defined for the evaluation method On change. It allows to restrict the evaluation of given expression so that the expression will be evaluated once within the defined time. It is used especially in cases, when the values of the objects defined in the expression are often changed and immediate calculation of the expression is not required.

Eval tags