to determine max and min value from DB

plc2000 · Jun 25, 2009

Hi

I am trying to determine (online) max and min value from DB. Anybody may help me and give me any example how I may to cope with this problem ??

I will be grateful for help.

Greetings

rdrast · Jun 25, 2009

SELECT MIN(column_name) FROM table_name

SELECT MAX(column_name) FROM table_name

gbradley · Jun 25, 2009

Do a Search on this site for Bubble sort.
There are some great reads like this one.

plc2000 · Jun 25, 2009

ok, but I must know how I may do this for STL language

L D[AR2P#0.0] · Jun 25, 2009

What data type is in the DB ? int, dint, or real ?

plc2000 · Jun 25, 2009

L D[AR2P#0.0] · Jun 25, 2009

Source code below:

Code:

FUNCTION FC 1 : VOID
TITLE =
VERSION : 0.1

VAR_INPUT
  dbData : BLOCK_DB ; 
END_VAR
VAR_OUTPUT
  rMax : REAL ; 
  rMin : REAL ; 
END_VAR
VAR_TEMP
  iLoopCount : INT ; 
END_VAR
BEGIN
NETWORK
TITLE =
      L     -3.402823e+038; 
      T     #rMax; 
      L     3.402823e+038; 
      T     #rMin; 
      LAR1  P#DBX 0.0; 
      OPN   #dbData; 
      L     DBLG; 
      L     4; 
      /D    ; 
L1:   T     #iLoopCount; 
      L     #rMax; 
      L     D [AR1,P#0.0]; 
      >=R   ; 
      JC    t2; 
      T     #rMax; 
t2:   L     #rMin; 
      >=R   ; 
      JC    t3; 
      TAK   ; 
      T     #rMin; 
t3:   +AR1  P#4.0; 
      L     #iLoopCount; 
      LOOP  L1; 
END_FUNCTION

plc2000 · Jun 25, 2009

thanks but this isn't STL language

TurpoUrpo · Jun 25, 2009

How you say that? THAT IS STL language.

As you failed to provide info on plc you use. LD assumed you use S7. And that indeed is STL of S7 system.

plc2000 · Jun 25, 2009

ok, but this code isn't accept by simatic step 7, my mistake this time is ok

L D[AR2P#0.0] · Jun 25, 2009

Create an stl source code block in your sources folder, open it, paste in the code, then compile it. FC1 will then appear in your blocks folder.

plc2000 · Jun 25, 2009

L 0
T MD 90

L 100 // loop 100 times
p1: T MW 50
OPN DB 2 // data type REAL
L MW 51
L 4
*D
SLD 3
L P#DBX 0.0
+D
LAR1

// find max value
L DBD [AR1,P#0.0]
L MD 90
>R
JCN p2
T MD 90
p2: T MD 91 // min value

L MW 51 // counter
L 1
+I
T MW 51

L MW 50
LOOP p1

I know this code is incorrect and isn't finish. Mayby someone help to finish this.

to determine max and min value from DB

plc2000

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L D[AR2P#0.0]

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L D[AR2P#0.0]

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L D[AR2P#0.0]

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