Value Ranges

Information

• Value ranges are gathered for each data item in the Data Items module.
• As a result, you have to do the following for each data item:
  • define a value range type in the VR type field, that specifies
    • whether the gathered value range takes effect, and
    • when the DI is calculated or checked.
  • define a formula for the value range itself in the Value range field.

Note

• Value ranges can be deactivated without the formula being deleted. For this purpose, delete the entry in the VR type field.

Value Range Type

Information

• There are three groups of value range types. Via value ranges, data items can be
  • checked as entry fields upon input (PL, PF)
  • calculated as output fields (CO)
  • checked, calculated, and changed with Python (PY)

Standard Value Ranges

PL: Check by List

Objective

• To check whether the data field input coincides with the defined values

The value range

• is a tabular list of permissible values.
• consists of Operatoren and Operanden.

Details

• Numeric data items
  • List of permitted input values separated by commas.

• Alphanumeric data items
  • Specify the list of allowed input values in quotation marks and separated by commas.

Notes

• When an incorrect input is made,
  • the "Please check entry" message is displayed and
  • the incorrect value will not be applied so that the previous value is displayed again.
• An entry is correct if it is an element of the value range.

PF: Check Using a Formula

Objective

• To check the data field input for values that result from the formulas

The value range

• is a check formula.
• consists of Operatoren, Operanden and possibly Functions.

Details

• A check formula must return the value 0 or 1, with:
  • 0: FALSE
  • 1: TRUE
• Only one formula can be specified for each DI.
• One formula may extend over several lines.

Example

Notes

• When an incorrect input is made,
  • the "Please check entry" message is displayed and
  • the incorrect value will not be applied so that the previous value is displayed again.
• An entry is correct if the value range formula returns the TRUE value.

CO: Calculations

Objective

• To calculate the output value of a field in accordance with the prescribed formula.

The value range

• is a calculation formula.
• consists of Operatoren, Operanden and possibly Functions.
• Only one formula can be specified for each DI.
• One formula may extend over several lines.

Notes

• For incorrectly constructed value ranges, the following error messages appear upon module start:
  • VR: division by zero
    • Attempt to divide a number by zero.
  • VR: result of calculation invalid (storage volume)
    • Result of the calculation exceeds the defined length of the virtual DI, e.g. when character chains are put together from constants or variables without the use of the TRIM() function.
  • VR: Operanden type incompatible
    • Attempt to execute a calculation between two different data types, e.g. a character string and a number. Convert relevant Operanden using the corresponding function, e.g. FMT(), ATOI().
  • VR is invalid: DIxxxxxx
    • Syntax error in the value range. Also follow-up message on the error messages listed above.
• Depending on the specific error, an error message is only displayed once in each session when the value range is opened for the first time. Afterwards , the value range will no longer be executed.

Construction Rule for the CO, PL, PF Value Ranges

Permissible Objects

Operators

• arithmetic: +, -, *, /, % (Modulo)
• logical:
  • AND: &&
  • OR: ||
  • NOT: !
• binary:
  • AND: &
  • OR: |
  • NOT: !
• Compare: <, =, >, <=, ==, >=, <>, != (means NOT)
• Quotation marks: „"
• Parentheses: ( )

Operands

• Data items: real, virtual
• Variables:
  • Users: @U
  • Dynamic: @D
  • Global: @G
  • System: @
• Program constant
• Fixed value: strings, numbers

data type

• Integer: 2-byte, 4-byte, mixed
• String: arbitrary number of characters (also matchcode*)

Rules

Rules for Operatoren

• Arithmetic, logical, binary and comparison operators can be separated by blank spaces between the Operanden. This has no functional significance, but helps with the readability of a value range.
• Quotation marks and parentheses must exactly enclose contents, i.e. blanks may only be included if they have a functional significance.
• If the Boolean value of a value range is to be inverted, i.e. FALSE is to be output instead of TRUE, the contents of the value range must appear in parentheses and the expression "!=1” must be appended.

Example

Details

• In value ranges, calculations can be performed using "modulo" (operator = %)

Example

Rules for Operanden

• The operand value can be
  • output directly (e.g. as part of a string) or
  • simply serve as part of a calculation

Example

Rules for input in value areas

• Data item: DI<DI ident number>
  • is always entered with the prefix DI.
• Variable: "@ <variable type> <variable number>"
  • are always specified in quotation marks. The cutting-off of redundant spaces at the end takes place automatically.

• Constant: CONST <"constant ID">
  • The constant ID is always specified in inverted commas. The cutting-off of redundant spaces takes place automatically.
• Fixed value:
  • Numbers must be specified without quotation marks if they are to be used in calculations. A number enclosed in quotation marks is interpreted as a string.
  • Strings must be enclosed in quotation marks.

Note

• The Operanden variable and constant must be trimmed in the value range if you do not want the entire data field length to be output as source (for constants, e.g. a length of 70).

Example

• The value output is the same as the value input:

Python Value Ranges

PY: Check, Calculation, Change

Information

• With Python value range functions, the functions from the Python Api and default Python functions, data items can be checked, calculated and changed.