Assigning Addresses And Initial Values In The Data Block Editor; Using The Symbol Table For Symbolic Addressing Of Variables - Siemens SIMATIC S7-200 System Manual

S7-200 Programmable Controller System Manual

Assigning Addresses and Initial Values in the Data Block Editor

The data block editor allows you to make initial data assignments to V memory (variable memory)
only. You can make assignments to bytes, words, or double words of V memory. Comments are
optional.
Data
Block
The data block editor is a free-form text
editor; that is, no specific fields are
defined for particular types of
information. After you finish typing a line
and press the Enter key, the data block
editor formats the line (aligns columns of
addresses, data, comments; capitalizes
V memory addresses) and redisplays it.
Pressing CTRL--ENTER, after
completing an assignment line,
auto-increments the address to the next auto-increments the address to the next
available address.
The data block editor assigns an appropriate amount of V memory based on your previous
address allocations and the size (byte, word, or double word) of the data value(s).
The first line of the data block must have an explicit address assignment. Subsequent lines can
have explicit or implicit address assignments. An implicit address assignment is made by the
editor when you type multiple data values after a single address assignment, or type a line that
contains only data values.
The data block editor accepts uppercase or lowercase letters and allows commas, tabs, or spaces
to serve as separators between addresses and data values.

Using the Symbol Table for Symbolic Addressing of Variables

The symbol table allows you to define and edit the symbols that can be accessed by the symbolic
name anywhere in your program. You can create multiple symbol tables. There is also a tab in the
symbol table for system-defined symbols that you can use in your program. The symbol table is
Symbol
Table
also referred to as the global variable table.
You can identify the operands of the instructions in your program absolutely or symbolically. An
absolute reference uses the memory area and bit or byte location to identify the address. A
symbolic reference uses a combination of alphanumeric characters to identify the address.
For SIMATIC programs, you make global
symbol assignments by using the
symbol table. For IEC programs, you
make global symbol assignments by
using the global variable table.
To assign a symbol to an address: To assign a symbol to an address:
1. Click on the Symbol Table icon in the navigation bar to open the symbol table.
2. Enter the symbol name (for example, Input1) in the Symbol Name column. The maximum
symbol length is 23 characters.
3. Enter the address (for example, I0.0) in the Address column.
4. For an IEC global variable table, enter a value in the Data Type column or select one from
the list box.
You can create multiple symbol tables; however, you cannot use the same string more than once
as a global symbol assignment, neither within a single table nor among several tables.
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Figure 5-7 Data Block Editor
Figure 5-8 Symbol Table