Using Element Usage - Siemens Simatic S7-200 System Manual

Additional Features of STEP 7-Micro/WIN
5.5

Using Element Usage

You can use Element Usage to show the addresses and ranges that you have assigned in
your program. Element Usage shows this information in a more compact form than the
Cross Reference table. The range shown begins with the first used address, and ends with
the last used address. Unused addresses are shown as blank rows. See Figure 5-20.
There are two ways to view Element Usage:
Bit Format shows I, Q, M, and S
Byte Format shows V usage, AIW, AQW, MB, SMB, T, C, and HSC
Some considerations:
Within the Byte view, the double word address shows up as four consecutive D's. If there
are not four consecutive D's you may have used this address twice, or it may be a
deliberate programming effort. (A word shows up as two consecutive W's; a byte is one
B; and a bit is one b.)
Elements marked in usage with dashes (--) indicate ranged references. A ranged
reference results from addresses that are used by an instruction without being explicitly
stated. For example, the NET READ (NETR) instruction uses an 8-byte table in V
memory; however the first byte is the only explicit reference.
To generate a Element Usage table, select View
compiled and the Element Usage table appears. See Figure 5-20.You can leave the Element
Usage table up while you are entering your program. If you change the program, then click
into the Element Usage table, you must update the table by selecting the Refresh option that
appears at the top of the Element Usage screen.
Use View menu to
select Bit format
or Byte format.
Bit, Byte, Word, and
Double Word element
usage shown.
Figure 5-20
5-18
Element Usage (Compiled LAD View)
Option View
Byte 9
VB00000000
VB00000010
VB00000020
VB00000030
VB00000040
VB00000050
VB00000060
VB00000070
VB00000080
VB00000090
SMB000
SMB010
Viewing the Element Usage Table
Element Usage. Your program is
8 7 6 5 4 3 2 1
-- -- D D W
b
D D D
B
-- -- -- -- W
W W
S7-200 Programmable Controller System Manual
C79000-G7076-C230-02
0
W
D
B
W