How can i write max and min data online during acquisition

[Labdummy]

Hello,

I am not keen with programming and your help will be greatly appreciated.

I make temperature acquisition from an IR camera and I record online 38 different spots at a frequency of 10 samples/min.

I also record two temperatures from thermocouples at the same sampling rate.

I would like to make the acquisition during 5 sec every 20 sec and extract the max and min temperature from the thermocouples and write these values in a text file like show below :

Temp_max 5 sec 22.1

Temp_min 5 sec 2.1

Temp_max 10 sec 42.1

Temp_min 10 sec 4.1

Temp_max 15 sec 82.1

Temp_min 15 sec 6.1

I also would like to make the same with two or three different spots of the IR camera. I think that if I have a good solution for the thermocouple, I can make it for the camera.

I use LabView 8.2 with NIDaqmx acquisition.

Thank you in advance

[Evrem_Y]

Hi Labdummy,

NI is giving courses and I highly recommend you to attend at least the LV Basics 1 course. After the course you will be able to create this kind of apps and more!

Do you have anything programmed?

Or, what exactly is causing headache? The data acquisition, timing or saving the datas into files?

With Best Regards,

Evrem

[Labdummy]

Hello Evrem,

Thank you for your advice. In fact, I have already attended to the training course you mentioned. I should think about going to the module Basic II. I do not have problem to connect/pilot various type of instruments but I am not very efficient with loop and arrays !

I am fine with the data acquisition and the timing and I can sort data during 5 sec with "Array max & min". Then, I can display all data. What I have problem to do is to extract the max & min from the array, keep these 2 values for being writtten in a file at the end of my loop and start again during the next 5-sec cycle. At present, I only have the last max & min results from the last acquisition !

Any example of how recording max & min online during 5-sec cycle acquisition will be welcome.

Best regards,

Labdummy

[Andre_Saller]

If you have attended the LabVIEW Basics 1, then check out the manual in Chapter 4. The relevant topic is "shift registers". There is an exercise dealing with this topic as well: Ex 4-4.  With shift registers, you can pass data from one loop-run to the next.

Another thing inportant topic would be "auto indexing". With outoindexing, you can store data acquired/generated in a loop in an array automatically, so you get EVERY value, not only the last one. This topic is dicussed in detail in capter 5, concerning arrays.

have a look at Ex 5-1 as well.

Hope this helps!

André