118
Internal Work Area
Section 4-5
4-5
Internal Work Area
The Internal Work Area contains 512 words with addresses ranging from W0
to W511. These words can be used in programming as work words.
There are unused words in the CIO Area (CIO 3800 to CIO 6143) that can
also be used in the program, but use any available words in the Work Area
first because the unused words in the CIO Area may be allocated to other
applications when functions are expanded.
Forcing Bit Status
Bits in the Work Area can be force-set and force-reset.
Work Area Initialization
The contents of the Work Area will be cleared in the following cases:
1.
When the operating mode is changed from PROGRAM to RUN or MONI-
TOR mode or vice-versa and the IOM Hold Bit is OFF
2.
When the power is cycled
3.
When the Work Area is cleared from the CX-Programmer.
4.
When PLC operation is stopped when a fatal error other than an
FALS(007) error occurs. (The contents of the Work Area will be retained
when FALS(007) is executed.)
4-6
Holding Area (H)
The Holding Area contains 512 words with addresses ranging from H0 to
H511 (bits H0.00 to H511.15). These words can be used in programming.
Holding Area Initialization
Data in the Holding Area is not cleared when the power is cycled or the PLC’s
operating mode is changed from PROGRAM mode to RUN or MONITOR
mode or vice-versa.
A Holding Area bit will be cleared if it is programmed between IL(002) and
ILC(003) and the execution condition for IL(002) is OFF. To keep a bit ON
even when the execution condition for IL(002) is OFF, turn ON the bit with the
SET instruction just before IL(002).
Self-maintaining Bits
When a self-maintaining bit is programmed with a Holding Area bit, the self-
maintaining bit won’t be cleared even when the power is reset.
Note
1.
If a Holding Area bit is not used for the self-maintaining bit, the bit will be
turned OFF and the self-maintaining bit will be cleared when the power is
reset.
2.
If a Holding Area bit is used but not programmed as a self-maintaining bit
as in the following diagram, the bit will be turned OFF by execution condi-
tion A when the power is reset.
3.
H512 to H1535 are used as a Function Block Holding Area. These words
can be used only for function block instances (internally allocated variable
area). These words cannot be specified as instruction operands in the user
program.
H0.00
H0.00
A
H0.00
Содержание CP1L-EL20DR-D
Страница 3: ...CP1L EL20D CP1L EM30D CP1L EM40D CP1L EL EM CPU Unit Operation Manual Produced July 2017...
Страница 4: ...iv...
Страница 10: ...x...
Страница 22: ...xxii...
Страница 34: ...xxxiv Software Licenses and Copyrights 7...
Страница 178: ...144 Connecting the CX Programmer Section 5 1 Click the Connect button to connect and then connection online is completed...
Страница 192: ...158 Trial Operation and Debugging Section 5 3...
Страница 250: ...216 Automatic Clock Adjustment and Specifying Servers by Host Name Section 6 7...
Страница 666: ...632 Trouble Shooting Section 11 7...
Страница 696: ...662 Standard Models Appendix A...
Страница 805: ...771 Connections to Serial Communications Option Boards Appendix F Connecting to Unit...
Страница 806: ...772 Connections to Serial Communications Option Boards Appendix F...
Страница 836: ...802 PLC Setup Appendix G...
Страница 838: ...804 TCP Status Transitions Appendix H...
Страница 840: ...806 Ethernet Network Parameters Appendix I...
Страница 842: ...808 Buffer Configuration CP1L EL EM Appendix J...
Страница 844: ...810 Ethernet Specifications Appendix K...
Страница 851: ...Index 817 work words 118 write protection 447...
Страница 852: ...818 Index...
Страница 854: ...820 Revision History...
Страница 855: ......