Chapter 6 Applied Instructions Symbol S 1 ： Data source1 S 2 ： Data source2 Taking LD$= for example Explanation 1. These instructions compare the strings in S 1 and S 2 . 2. S 1 and S 2 can contain strings up to 256 characters(16#00 the end symbol is included). 6_ 3. Take the instruction LD$= for example. When the comparison result is that the value in S 1 is equal to that in S 2 , the continuity condition of the instruction is met. When the comparison result is that the value in S 1 is not equal to that in S 2 , the discontinuity condition of the instruction is met. 4.
Only when the data in S – S +n (n indicates the n th device, up to 256 characters in each string) includes 16#00 can the data be compared complete strings. For example: b15 b8 b7 b0 S 16#32(2) 16#31(1) S+1 16#34(4) 16#33(3) S+2 16#35(5) 16#00 " " 12345 6-19 API Instruction code Operand Function 0036-0037 LD$※ S1，S2 Comparing strings LD$※ Device X Y M S T C HC D FR SM SR E K 16# “$” F S1 S2 BOOL WORD DWORD LWORD UINT INT DINT LINT REAL LREAL TMR CNT STRING Data type S1 S2 Pulse Instruction 16-bit instruction 32-bit instruction - ES3 - 16-bit Continuity Discontinuity API number instruction condition condition 0036 LD$＝ S1＝S2 S1≠S2 0037 LD$＜＞ S1≠S2 S1＝S2