64 bit counter

kreacher · Sep 9, 2015

Hi,

I have a question. Does anyone have any ideea on how to create a counter that can go above 32767? I have seen in Siemens PLC that the high limit of counters is 32767 but i need a much much bigger number.

How can i do this?

Thank you,

Kreach

RussB · Sep 9, 2015

Most all PLC's will have an ADD function to a DINT that you can count to at least once per scan. Some like the GE-IP PLC/PAC can Add multiple times per scan. If you need to count very fast get a High Speed Counter for your processor.

kreacher · Sep 9, 2015

I am using a 315 Siemens PLC. How can i do what you mentioned?

dploof23 · Sep 9, 2015

I think you need a 32 bit timer, not 64. a 16 bit word maxes out at 32767, with a 32 bit double word you can go up to 2,147,483,647 (signed).

Unfortunately I have no experience with the PLC platform you are using.

Hope this helps,
Dave

JOLTRON · Sep 9, 2015

Create a new memory location in a Datablock (or a M address) and define it as 'DINT'

Then feed this address into a 'Add_DI' block from the 'Integer function' section.

The other input will need to be a 1 and the output will be the address you created.

L D[AR2P#0.0] · Sep 9, 2015

Source code for a 32 bit counter using the same interface as SFB0 from the standard library:

Code:

FUNCTION_BLOCK FB 1
TITLE =
VERSION : 0.1


VAR_INPUT
  CU : BOOL ;    
  R : BOOL ;    
  PV : DINT ;    
END_VAR
VAR_OUTPUT
  QQ : BOOL ;    
  CV : DINT ;    
END_VAR
VAR
  bEdgeStore : BOOL ;    
  diCount : DINT ;    
END_VAR
BEGIN
NETWORK
TITLE =

      A     #CU; 
      FP    #bEdgeStore; 
      JCN   res; 

      L     #diCount; 
      L     L#1; 
      +D    ; 
      JP    pos; 
      JU    res; 
pos:  T     #diCount; 
res:  A     #R; 
      JCN   nors; 
      L     L#0; 
      T     #diCount; 
nors: L     #diCount; 
      T     #CV; 
      L     #PV; 
      >=D   ; 
      =     #QQ; 



END_FUNCTION_BLOCK

grnick50 · Sep 9, 2015

You can use IEC timers from the Standard library.

kreacher · Sep 9, 2015

Why is everyone mentioning Timers? I need a Counter...
And unfortunately it must be bigger, at least 62 bits... this is what was asked of me.

And i have tried already what Joltron said. But it doesn't do what i need it to do. If i leave the EN Input free it only does 1 Addition. If i try to put my clock there it does more ADD operations but not in the rhythm of the clock. When the Clock is 0 it doesn't do anything but when the Clock is 1 it does multiple operations. Any clue why?
Thank you very much guys.

Doug-P · Sep 9, 2015

kreacher said:
I need a Counter...
And unfortunately it must be bigger, at least 62 bits... this is what was asked of me.

kreacher said:
Does anyone have any idea on how to create a counter that can go above 32767? I have seen in Siemens PLC that the high limit of counters is 32767 but i need a much much bigger number.

These are two different things. Is the requirement to use a certain number of bits or, is it to count up to a certain value? Does the value need to fit into one unit (word/dword) or can it be spread over multiple units?

kreacher · Sep 10, 2015

The ideea of this exercise is to make a Counter that can count up to a maximum of at least 2^62.
And it does not say but i think it must fit into 1 unit, probably a 64 bits DREAL? I'm very inexperienced with number processing and SCL/STL. So far mostly i've only worked with LAD or FBD.

bkottaras · Sep 10, 2015

There's no DREAL.
A LREAL instead?
(Long Real).
What are you using as the clock pulse?
A Positive Transition bit should do the trick.
Use a P-Trigger instruction as your pulse (Clock) and tie the Trigger.Q to the Enable of the the ADD instruction.

kreacher · Sep 10, 2015

As a pulse clock i am using the internal PLC clock. And yes LREAL.

bkottaras · Sep 10, 2015

Use a P-Trigger instruction as the Clock.
The internal clock is your problem I think as it is on for the duration (more than one scan).

kreacher · Sep 10, 2015

I understand, thank you, i have a question though.

At the output of the ADD i have a MW which is a integer. How can i make it so that i can use a LREAL to be able to count up to 2^62 or even more? I know LREAL should be 64 bits?

bkottaras · Sep 10, 2015

If you look at Joltron's post, he defined an MD as the counter.
That should do it, define an MD as long real.

64 bit counter

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