Text Selectors

Help Contents

Introduction

Many SCADA applications use data provided in text form. For example:

A Text Selector is a way of locating a field or value within a text document. For example the Text Selector Line(5) returns line number 5 from a plain text document.

Fernhill SCADA uses Text Selectors in these areas:

Text Selector Syntax

A Text Selector uses this syntax:

Read-Transform ::=
    { JSON-Read-Transform | CSV-Read-Transform | Line-Read-Transform }

JSON-Read-Transform ::=
    'JSONata(' JSONata-Expr ')'

CSV-Read-Transform ::=
    'CSV(' Cell-Reference ')'

Line-Read-Transform ::=
    'Line(' Line-Number ')'

Where:

Examples

  1. Read the first line of a plain text document:
    Line(1)
  2. Read row 2 and column 3 of a CSV document:
    CSV(C2)
  3. Read an array element of a JSON formatted document:
    JSONata(A[4])

Further Information

Fernhill SCADA Concepts

To learn about other Fernhill SCADA Concepts.

Glossary

For the meaning of terms used in Fernhill SCADA.