_dp_fct (DP function)

Dp function

The config attributes can be found in the Appendix.

DP function panel

If you selected DPE link as the function type, pressing the button Configure will open the following panel:

Parameters

The Parameters list lists the parameters to be linked when calculating the function.

• Enter new parameters in the Parameters list.

• The order of parameters is specified using the buttons (see Buttons). The current item is displayed selected in the list of parameters.

• Selected items can be removed from the list by pressing Delete.

• You can edit selected items in the "Value of a DPE as parameter p.." table by left-clicking the item in the table, entering a new DPE into the "p..=" text field and then clicking the button . The selected item is replaced by the item in the "p..=" text field.

• The button DP is used to enter data point parameters. Click this button to open the Data pointSelector dialog box.

Configure equal data point elements (with different configs) only sequentially, to avoid equal internal times. Otherwise you cause error messages.

In the same way you can define the global variable for data point functions. Global variables are, however, only called once, after which changes in values are not taken into account. This means that the function value is always multiplied by the same value of g1.

Function

This field is used to define the data point function and to link parameters with each other. Permissible inputs are defined parameters p1, p2, ... and mathematical links. Mathematical operators +,-,*,/,%,&,|,^,~,<<,>>, &&, ||, ?, <,>,<=,>=,==,!=,++ can be used, see chapter Operators in CONTROL.

An assignment by using = is not permitted!

You can also use a Control function with a return value. Note that waiting functions ( dpSetWait, delay, dpQuery …) are not permitted. Furthermore, the system() function is not permitted.

The following code is generated for a dpFunction:

anytype work(anytype p1, … anytype pn)
{
  return <string of the edit line in PARA>;
}
EXAMPLE: p1 + p2 are used as follows:
anytype work(anytype p1, anytype p2)
{
  return p1 + p2;
}
The expression must be a valid CTRL script. By using a function, you can also use it as follows:
If a dp_fct dynlen(p1) is configured for an integer DPE and p1 is a dyn DPE:
anytype work(anytype p1)
{
  return dynlen(p1);
}

If you call a function of a CTRL library ( <proj_path>/libs) in the "Function" text field you can use the return value of the function for the calculation.

Old new Comparison

You can activate old/new comparison for this data point function by ticking this check box.

Statistical functions

Parameters tab

• The name (and description or alias) of the data point element to be edited is displayed at the top right of the panel in the combo box.

• The data point attributes are selected using the DP selector button or entered directly in the input box. This input is mandatory.

• The 4 buttons are used to add the item before or after the last item, and to edit or delete the item.

• Alongside there is a combo box in which you can select various statistical functions.

• Below that you can specify the global variable (optional). The variable is only called once, as in DP functions, changes of values are not taken into account (see above).

• The result of the function is defined in the bottom input box.

Minimum and maximum values are calculated from the stepped curve interpolation and not from the series of values, i.e. minimum and maximum time are always in the current range and if no new values occur during an interval, minimum and maximum contain the first known value of an interval as time stamp.

Both integral functions return their result in the unit: unit of base variable multiplied by seconds.

Synchronization tab

The time of calculation is set on the Synchronization tab.

Bit tab

On the Bit tab you can specify what effect status bits have on calculations.

It is also possible to add the quality information to the result value.

A column lists all bits that can affect the calculation. You can set one threshold per bit. To do so, enter a value in the appropriate field.

Select from the following options in the Status bit handling combo box:

• None: The status bit is not taken into account for calculation (default).

• Ignore Value: values for which this bit is set are processed as if they had never occurred, the calculation period for statistical functions is not affected by this. If you have specified that value or time bits are processed for several bits, the affected bits are combined by an OR and the result bit is used for calculation. Moreover, all of these bits must have the same status bit treatment configured. Otherwise a parameter error will occur (if, e.g., the ASCII Manager inputs such data).

• Ignore Period: the period in which the bit was set is not taken into account for calculation. If you have specified that value or time bits are processed for several bits, the affected bits are combined by an OR and the result bit is used for calculation. Moreover, all of these bits must have the same status bit treatment configured. Otherwise a parameter error will occur (if, e.g., the ASCII Manager inputs such data).

• Transfer Bits: The status bit is not taken into account for the calculation. Additionally the status bit is transferred according to the selected threshold. In other words the status bit is set for the _original config of the data point element for which the _dp_fct was activated.

The threshold is a value in per cent and is evaluated as follows:

• If the bit is set the same length or longer from the calculation interval than the time Threshold %, the bit from the column "added status bit" is set in the result bit (the bits "invalid" and "default" are read-only attributes and cannot be added directly).

• If threshold = 0%, every occurrence causes the bit to be added.

• If it is a negative value (default = -1) the bit is never added. The "aut_inv" bit is already set in the current statistical functions when internal errors occur. This invalid state is linked with the OR derived from the "invalid" bit.

Correction values and statistical functions

Correction value handling has been added to the statistical DP functions. This is performed automatically when you register the DP function to the config "_offline.._value" (but not for _original/_online.._value). Details:

The user sends a correction value xx.:_corr.._value to a data point that is the source for another statistical function. In this case, the Event Manager recalculates the statistical function. Two cases are possible:

Interval not yet calculated:

If the interval has not been calculated, the correction value is included in the current calculation at the end of the interval. The following also applies:

• the dependent value (the daily value in the examples) is only marked as a correction value if the change is greater than statFctLimitForMarkAsCorrcted (default: 0; see below) in relation to the non-corrected daily value.
• Otherwise, the value is sent without correction. For this decision, the value WITHOUT corrections (online value) is compared to the value WITH corrections (offline value) (see Config entry statFctInheritCorrValues).

Interval already calculated

If the interval is already finished, the calculation must be performed from the history values in order to mark a value as a correction value.

This correction value can then be used for calculation of another statistical function (recursion!).

statFctInheritCorrValues

You can set the behavior of statistical functions in the config file. The config entry statFctInheritCorrValues (type: bool, default: 1) decides whether the correction values should be accepted. By default, the correction value changes are accepted.

[general]
statFctInheritCorrValues = 1

If 0, changes are not accepted, the statistical functions work as usual.

statFctLimitForMarkAsCorrected

[general]
statFctLimitForMarkAsCorrected = 0

If 0, all values are marked as corrected. Values greater than 0 only mark values as of a change greater than x %%.

The correction values that are set for the statistical functions, trigger a recalculation exclusively in the period where they were set. The following periods are not recalculated.

If a correction value has an influence on the last value of the period, also the following period should be recalculated as long as the correction value does not cause a change in the following periods, compared to the original values.