90
6.4.5 String comparison
Input / output
Operand
Data type
IN1
VB, Constant string, LB, *VD, *LD, *AC
String
IN2
VB, LB, *VD, *LD, *AC
String
Output
(
FBD
)
I, Q, M, SM, T, C, V, S, L, Enable bit
Boolean
Comparison string instructions are used for comparing
two ASCII strings: IN1=IN2
,
IN1<>IN2
In LAD, when the comparison result is true, the
comparison contact will be turned on.
The maximum length of a single constant string is 126
bytes.The maximum combined length of the two constant
string is 242 bytes.
Attention:The following conditions are serious errors .
These errors will cause the PLC to immediately stop the execution of the program:
1.Enter illegal indirect address.
2.Enter a string of more than 254 characters in length.
3.The start address and length of the string cannot be put into a specified memory
area.
ASCII constant string data type format:
String is a series of characters and the corresponding memory address, each
character is stored in a byte.The value of the first byte of a string is the length of the
string.If a constant string is entered directly into the program editor or data block,
the string must start and end with double quotation marks ("string constant").
The following memory map shows the format of the string data type.The length of a
string can be between 0 and 254 characters.The maximum length of the string is 255
bytes.
String
length
Character
1
Character
2
Character
3
Character
4
Character
5
..................................
Character
254
Byte 0
Byte 1
Byte 2
Byte 3
Byte 4
Byte 5
Byte 254
Содержание PR-12 Series
Страница 26: ...19 1 xLogic CPU PR 12 Series CPU PR 14 and PR 18 series 1 PR 18 CPU 2 PR E extension...
Страница 27: ...20 PR 24 series...
Страница 47: ...40 5 3 Instruction tree...
Страница 50: ...43 CAN interface PLC supports CAN communication CAN communication will be introduced in the communication block...
Страница 54: ...47 Force table interface When PLC is converted from RUN mode to STOP mode the selected output points will be 1...
Страница 58: ...51 5 3 10 Instructions Instructions will be explained in detail in the instructions section...
Страница 73: ...66 2 Select the PLC model ensure that the PLC model in the software is consistent with the actual PLC model...
Страница 93: ...86 2 Enter the illegal real number Example...
Страница 127: ...120 Example...
Страница 137: ...130 Kc gain TD Differential time Ts Sampling time PVn 1 Last time process variable PVn Process variable...
Страница 139: ...132 Special memory bit SM1 0 Zero result SM1 1 overflow SM1 2 Negative result Example...
Страница 143: ...136 Special memory bit SM1 0 Zero result SM1 1 overflow SM1 2 Negative result SM1 3 The divisor is 0 Example...
Страница 149: ...142 Example...
Страница 152: ...145 Example ATCH instruction only needs to be connected once...
Страница 154: ...147 Example...
Страница 172: ...165 Example Notes Cycle times are set to 100 times At the end of the cycle the value of VW100 is 100...
Страница 175: ...168...
Страница 182: ...175 Example When the value of M0 0 is 1 VB0 moves a bit towards the left and VB10 moves a bit towards the right...
Страница 217: ...210 Example Four arithmetic operation Main program...
Страница 218: ...211 Subroutine...
Страница 252: ...245 10 8 Example of serial port free port communication Program 1...
Страница 254: ...247 10 9 Example of CAN free port...
Страница 256: ...249 10 10 MODBUS communication master program Read multiple hold registers and write multiple hold registers...
Страница 258: ...251 Conversion of Process quantity and set value unit...
Страница 259: ...252 Call a PID command every 0 3 seconds...
Страница 260: ...253 The conversion of output value unit...