Mitsubishi Electric MELSEC FX3U Programming Manual page 7

FX /FX /FX Series Programmable Controllers
3G 3U 3UC
Programming Manual - Basic & Applied Instructions Edition
5. How to Specify Devices and Constants to Instructions
5.1 Numeric Values Handled in PLCs (Octal, Decimal, Hexadecimal and Real Numbers) .............. 158
5.1.1 Types of numeric values.............................................................................................................. 158
5.1.2 Conversion of numeric values ..................................................................................................... 159
5.1.3 Handling of numeric values in floating point operations .............................................................. 160
5.2 Specification of Constants K, H and E (Decimal, Hexadecimal and Real Number).................... 162
5.2.1 Constant K (decimal number)...................................................................................................... 162
5.2.2 Constant H (hexadecimal number).............................................................................................. 162
5.2.3 Constant E (real number) ............................................................................................................ 162
5.3 Character Strings ........................................................................................................................ 163
5.3.1 Character string constant ("ABC") ............................................................................................... 163
5.3.2 Character string data ................................................................................................................... 163
5.4 Specification of Digits for Bit Devices (Kn[ ]***)........................................................................... 164
5.5 Bit Specification of a Word Device (D[ ].b) .................................................................................. 165
5.6 Direct Specification of Buffer Memory (U[ ]\G[ ]) ......................................................................... 165
5.7 Indexing....................................................................................................................................... 166
5.7.1 Indexing in basic instructions....................................................................................................... 166
5.7.2 Indexing in applied instructions ................................................................................................... 167
5.7.3 Indexing example for instruction with limited number of use. ...................................................... 169
6. What to Understand before Programming
6.1 How to Read Explanation of Instructions .................................................................................... 171
6.2 Cautions on Creation of Fundamental Programs........................................................................ 174
6.2.1 Programming procedure and execution order ............................................................................. 174
6.2.2 Double output (double coil) operation and countermeasures...................................................... 175
6.2.3 Circuits which cannot be programmed and countermeasures .................................................... 176
6.3 I/O Processing and Response Delay .......................................................................................... 177
6.4 Mutual Relationship Among Program Flow Control Instructions................................................. 178
6.5 General Rules for Applied Instructions........................................................................................ 180
6.5.1 Expression and operation type of applied instructions ................................................................ 180
6.5.2 Handling of general flags............................................................................................................. 182
6.5.3 Handling of operation error flag ................................................................................................... 184
6.5.4 Handling functions of extension flag............................................................................................ 185
6.5.5 Limitation in number of instructions ............................................................................................. 185
7. Basic Instruction
7.1 LD, LDI ........................................................................................................................................ 189
7.2 OUT............................................................................................................................................. 191
7.3 AND, ANI..................................................................................................................................... 194
7.4 OR, ORI ...................................................................................................................................... 197
7.5 LDP, LDF, ANDP, ANDF, ORP, ORF ......................................................................................... 200
7.6 ORB ............................................................................................................................................ 206
7.7 ANB............................................................................................................................................. 207
7.8 MPS, MRD, MPP ........................................................................................................................ 208
7.9 MC, MCR .................................................................................................................................... 213
7.10 INV ............................................................................................................................................ 216
7.11 MEP, MEF................................................................................................................................. 217
7.12 PLS, PLF................................................................................................................................... 219
7.13 SET, RST .................................................................................................................................. 221
7.14 NOP .......................................................................................................................................... 224
7.15 END........................................................................................................................................... 225
7.16 Number of Instruction Steps and Specified Devices ................................................................. 226
Table of Contents
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