ProSoft Technology 5204SE-MNET-PDPMV1 - Manual (Page 95)

Reference 5204SE-MNET-PDPMV1 ♦ ProLinx Gateway
User Manual Modbus TCP/IP to PROFIBUS DP-V1 Pass-Through Master
ProSoft Technology, Inc.
Page 95 of 235
December 22, 2009
4 Reference
In This Chapter
™ Basics of Working with Unity Pro........................................................ 95
™ Unity Pro Program Objects and Organizing Structures ........................ 96
™ Modbus TCP/IP Communication Control in M340 and Quantum PACs 97
™ Modicon M340 Variables, Derived Data Types, and Derived Function
Blocks ............................................................................................... 98
™ Modicon Quantum Variables, Derived Data Types and Derived Function
Blocks ............................................................................................. 137
™ PROFIBUS Acyclic Telegram (Message) Block Structures ................ 194
™ Mailbox Messaging Error Codes....................................................... 218
4.1 Basics of Working with Unity Pro
Before launching into descriptions of the Variables, Derived Data Types (DDTs)
and Derived Function Blocks(DFBs) that are automatically created by the
Application Communication Logic functions of ProSoft Configuration Builder
(PCB), it might be helpful to give a quick overview of these Unity Pro structures.
Derived Data Types (DDTs) provide the basic building blocks for more complex
Unity Pro data structures. They are used by both Variables and Function Blocks
as a way to organize and define the characteristics of individual pieces of data.
These characteristics will be shared by all instances of the data type. DDTs
specify a data item's:
ƒ Structure
ƒ Format
ƒ List
of attributes
ƒ Behavior
Variables are the basic data storage unit in Unity Pro programming software.
Variables allow a processor to hold and manipulate data values using application
process logic. Variables will be identified by a unique name (sometimes referred
to as symbols) and will be assigned to hold a particular type of data, like binary or
Boolean values (zeros and ones), signed or unsigned integer values of various
sizes (8-, 16-, or 32-bit data), floating point values, alpha-numeric strings, arrays
(numbered groups of the same type), DDTs, and more.