i have four analog inputs. I convert them to integers.

Later i want to take a decision solving an recursive algorithm with these 4 integers (dynamic programming).

I have the algorithm in java and i would like to ask how i could "write" it to be suitable for plc because the computation cycle of plc is different from a pc language .

For example the integers are "3,2,7,1," and i want to use only these which the sum of them is 6.

3+2+1=6 so i need the first the second and the fourth.

The algorithm is: http://algorithms.tutorialhorizon.com/dynamic-programming-subset-sum-problem/

If you see i must call again and again the method(function) find.

Can i do something similar using plc or not??

Hello,

giving only my personal opinion. I think impossible in this way, also you have probably understand that 'PC' application functionality is other type like PLC. Simply in PLC you need be basically quicker than Scan time set on PLC. Nested (also recursively) called functions, loops logically can harm PLC code functionality, we don't want some kind of timeouts. Also I'm not so good mathematic but also there is condition with some severity with execution of alghoritm, simply in my opinion also on PC system recursive code can't simply run to 'long distance'. Also dangerous can be to not right defined code without good condition of return value. This can be very dangerous. Try think another system, this is my opinion.

Can you describe in general the application. There may be ways around doing this kind of algorithm contentiously dynamically.  For example there may be time that this algorithm can be executed and prepared or stored to be used even 500ms later or so.

Are there a set of expected results that the algorithm can have that it is possible to be executed for different scenarios and stored in arrays or structures and depending on requirement the right one is pulled out?

ze2pyrros

Later i want to take a decision solving an recursive algorithm with these 4 integers (dynamic programming).

First of all - direct recursion is not allowed. You will get compile error once you try. If you overcome this then you will find that the nesting stack is very shallow...

Second - dynamic memory management is not supported.

Typical PLCs implementations are very strict about above, as the BSOD is not an option during machine/process control.

If you really need to implement such an algorithm in a PLC you have to get rid of recursion and dynamically created variables.

Hello people,

On V14 it's possible to use direct recursive calls, only for 1x00 family. I don't know which firmwares will support it though.

TIA Portal V14 New Functions (pg 32)

Regards,