Table Find - Siemens SIMATIC S7-200 System Manual

Table Find

The Table Find instruction (FND) searches a table for data
that matches certain criteria. The Table Find instruction
searches the table TBL, starting with the table entry INDX,
for the data value or pattern PTN that matches the search
criteria defined by CMD. The command parameter CMD is
given a numeric value of 1 to 4 that corresponds to =, <>, <,
and >, respectively.
If a match is found, the INDX points to the matching entry in
the table. To find the next matching entry, the INDX must be
incremented before invoking the Table Find instruction
again. If a match is not found, the INDX has a value equal to
the entry count.
A table can have up to 100 data entries. The data entries
(area to be searched) are numbered from 0 to a maximum
value of 99.
Error conditions that set ENO = 0
H 0006 (indirect address)
H 0091 (operand out of range)
Table 6-71 Valid Operands for the Table Find Instruction
Inputs/Outputs Data Types
TBL WORD
PTN INT
INDX WORD
CMD BYTE
Tip
When you use the Table Find instruction with tables generated with the Add to Table,
Last-In-First-Out, and First-In-First-Out instructions, the entry count and the data entries
correspond directly. The maximum-number-of-entries word required for the Add to Table,
Last-In-First-Out, or First-In-First-Out instructions is not required by the Table Find instruction.
See Figure 6-36.
Consequently, you should set the TBL operand of a Find instruction to one-word address (two
bytes) higher than the TBL operand of a corresponding the Add to Table, Last-In-First-Out, or
First-In-First-Out instruction.
Table format for ATT, LIFO, and FIFO
VW200 0006
VW202 0006
VW204 xxxx
VW206 xxxx
VW208 xxxx
VW210 xxxx
VW212 xxxx
VW214 xxxx
Figure 6-36 Different Table Formats between the Table Find Instruction and the ATT, LIFO, and FIFO
Instructions
Operands
IW, QW, VW, MW, SMW, T, C, LW, *VD, *LD, *AC
IW, QW, VW, MW, SMW, SW, T, C, LW, AC, AIW, *VD, *LD, *AC, Constant
IW, QW, VW, MW, SMW, SW, T, C, LW, AC, *VD, *LD, *AC
(Constant) 1: Equal (=), 2: Not Equal (<>), 3: Less Than (<),
4: Greater Than (>)
TL (max. no. of entries)
EC (entry count)
d0 (data 0)
d1 (data 1)
d2 (data 2)
d3 (data 3)
d4 (data 4)
d5 (data 5)
S7-200 Instruction Set
Table format for TBL_FIND
VW202 0006 EC (entry count)
d0 (data 0)
VW204 xxxx
VW206 xxxx d1 (data 1)
VW208 xxxx d2 (data 2)
VW210 xxxx d3 (data 3)
VW212 xxxx d4 (data 4)
VW214 xxxx d5 (data 5)
Chapter 6
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