Omron CX-Programmer 9, Operation Manual

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PART 1: CX-Programmer
CHAPTER 2 – Quick Start Guide OMRON
CX-Programmer _Page 26
The global/local, name, address/value, and I/O comment fields for the symbol at the cursor position can be
displayed in the symbol bar below the Ladder Section window (CX-Programmer Ver. 4.0 or later). Enable this
function by selecting
Show symbol bar in the Diagrams Tab in the Options Dialog Box of the Tools Menu (the
default setting is ON: display). Therefore, while increasing the program display density, the text in particularly
long I/O comments can be checked, thereby improving the readability of the program.
Mnemonics View
The Mnemonics view is a formatted editor for programming in mnemonic instructions. This view is made up of
a table of six columns containing the rung number, step number, instruction, operands, value and comment.
Mnemonic instructions are a ‘low-level’ view of a PLC program, whilst ladder is higher. Since the ladder
program is just a higher-level representation of the mnemonic instructions, it is possible to type in mnemonics
and see the ladder program update.
Select the View Mnemonics button from the toolbar. The Mnemonics view is displayed in the
Diagram Workspace.
1, 2, 3… 1. To program in mnemonics, open the mnemonic view and place the cursor on the desired
instruction.
2. Press ENTER – this will enter the editing mode.
3. Edit or type the new instruction lines. A mnemonic instruction consists of an instruction
name followed by a set of operands separated by spaces (e.g. ‘MOV #1 A2’).
4. Either press ENTER to move to the next line, or press ‘down’ or ‘up’ on the keyboard to
move to another line – the updated line is still kept.
The newly entered information is separated out over the columns in the table.
5. When finished with editing, press ‘Esc’ to come out of editing mode.
Whilst entering a program in the mnemonics view, the ladder view shows the instructions in the new rung as
statement list. Once enough instructions have been entered to enable its drawing in ladder format it is redrawn.
Instructions can be transferred to and from the Mnemonics view using the standard Microsoft Windows Cut or
Copy and paste functions. For example, it is possible to paste a large amount of program from a text editor.
Refer to
Chapter 3 - Project Reference for further information.
Introducing Symbols and the Symbol Table
PLC addresses, which are used as operands in a PLC program, can be assigned a symbolic name and/or a
comment for the purpose of reference during programming. An address with a name or comment is known as a
Symbol.
A symbol table is an editable list of symbol definitions – the names, addresses and comments. This list also
provides information on the following:
♦
Rack location . If the address is contained within the PLC IO table, this shows the address’ rack location.
♦
Usage . If the address is contained within the PLC IO table, this shows the physical hardware type (i.e.
‘Input’ or ‘Output’) that is mapped to the address. If no hardware is mapped, ‘Work’ is shown, meaning that
the symbol is for general use.