Problem after testing 100 products

[MSARIKOC]

I use Labview to control a test machine. There is an 6251-M series DAQ board for analog signals to be acquired and PCI 6509 for Digital I/Os. I also control an AC motor drive via serial port(Enable, start, stop and speed ref.). The problem is after testing an amount of products(e.g. 100) the cycle time of the test increases(from 10sec to 20-30-50sec). I saw that this caused of misreadings from serial port(because I read the speed via serial port to switch between steps). Why it doesn't happen at first and starts after making an amount of tests. What can I do about this. How can I make sure the readings to be the same everytime? And make the cycle time fixed.

[LuI]

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@MSARIKOC wrote:
I use Labview to control a test machine. There is an 6251-M series DAQ board for analog signals to be acquired and PCI 6509 for Digital I/Os. I also control an AC motor drive via serial port(Enable, start, stop and speed ref.). The problem is after testing an amount of products(e.g. 100) the cycle time of the test increases(from 10sec to 20-30-50sec). I saw that this caused of misreadings from serial port(because I read the speed via serial port to switch between steps). Why it doesn't happen at first and starts after making an amount of tests. What can I do about this. How can I make sure the readings to be the same everytime? And make the cycle time fixed.

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Maybe a memory leak?
Opening ressources (References and not closing them?
Creating a report string or logstring or log-array?
Greetings from Germany!
--
Uwe

[MSARIKOC]

Do you think this effect the serial port communication only. Because the other process is working fine, only the serial port communication have problem.

[LuI]

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@MSARIKOC wrote:
Do you think this effect the serial port communication only. Because the other process is working fine, only the serial port communication have problem.

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You might accumulate all those serial data fragments in a string which might eventually become quite large.
OR you might accumulate these fragments in a queue or whatever transfer mechanism.
OR you open a new queue etc with each test and fill it and leave it open.

Either you provide more data or your vi, otherwise this starts to become just wild guessing...

Greetings from Germany!
--
Uwe