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Member
celsosilva
Posts: 12
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Accepted Solution

How to stop and restart a measurement with a specific criteria?

Hey guys,

 

I'm burning my brains trying to figure out this problematic on my program.

 

For my research project I am using an O2 sensor that is coupled to a Labjack U12 card and therefore I am getting a constant value of 4 mg/L based on the switch on/off of a AC power plug (connected to the analog output) that is connected to the aeration system. So when I have 3,8 mg/L switches on the aeration and 4,2 switches off.

But I want to run this measurement for a specific time (maybe 10 min) and then stop the signal to the analog output. After sometime the O2 measurement will drop to values of 0 mg/L but I want that when it reaches a specific value (maybe 0,5 mg/L), stays still inactive for a specific period of time (maybe 2 min) and then activates again the signal to the analog output (cycle restart).

 

Is it possible to stabilish this concept using Dasylab? I would so grateful if you could help me with that!!!

 

I'm attaching 2 pictures, one from my actual block configuration at Dasylab and the other is the expected measurement after the new configuration.

 

Hugs and looking forward for suggestions,

Celso 

Member MHa
Member
MHa
Posts: 115
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Re: How to stop and restart a measurement with a specific criteria?

@celsosilva,

I think that the DASYLab addon "Sequence Generator" should be useful for this task. More details under http://www.mccdaq.com/daq-software/dasylab-upgrf2p.htm

Best regards,
MHa

Member
hw70
Posts: 62

Re: How to stop and restart a measurement with a specific criteria?

Is the curve in the diagram the output of the "Labjack: Ai"-module?

 

Then you can use the following block-series:

Direct the signal from the Labjack-in-block into a combitrigger-block: Start-event is when the signal drops below 0,5, Stop-event is when the value rises above 0,5 (do NOT use events "is lower than"/"is greater than"!).

Connect the trigger-block to a counter-block, that counts the time the received signal (from the trigger-block) is TTL-high.

Use another trigger-block right after the counter-block: Start-event is when the signal rises above {insert time in seconds}, Stop-event is 'Direct'.

Now connect an action-block, that controls the corresponding aeration-switch (turn on: curve rises, turn off: curve drops -- is this correct?!), the action should fire, if the received signal from the previous block puts out a rising edge.

 

How to control the 10min-measurement-time with counter-, trigger-, switch-, and action-modules is left as homework. :smileywink:

 

 

M.Sc. Holger Wons | measX GmbH&Co. KG, Mönchengladbach, Germany | DASYLab, DIAdem, LabView --- Support, Projects, Training | Platinum National Instrument Alliance Partner | www.measx.com
Member
celsosilva
Posts: 12
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Re: How to stop and restart a measurement with a specific criteria?

the curve in the diagram is not the output of the ""Labjack: Ai"-module".

 

The output of the Labjack: Ai"-module just gives a signal to the AC power plug that is connected to the aeration system. I am not sure if your configuration is going to work but i will try it tomorrow but many thanks for the help :smileyhappy:

 

Do you know if it is possible to connect the action-block to an TTL-Pulse generator (that is connected to the relay-block) and after the expected 2 min it resets the TTL-Pulse generator (even if the Phase 2 is still not finished)??

Member
celsosilva
Posts: 12
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Re: How to stop and restart a measurement with a specific criteria?

It did work!! :smileyvery-happy:

 

I tried the block-series: trigger-, counter- , trigger, -action and worked perfectly!! To solve the 10 min measurement time I used a TTL Pulse generator with 10 min Phase 1 connected to a relay. So when the sensor reaches values of less then 0,5 starts a countdown of 2 min and then the action-block resets the TTL Pulse generator and a 10 min measurement starts again.

 

Many thanks to the member hw70 :smileyvery-happy: 

Member
Tiger진
Posts: 4
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Re: How to stop and restart a measurement with a specific criteria?

Sorry, I can't  write new message, so I write here.

I have a same problem but little diffrent...

 

I'm trying to get a singnal Lateral accelation using car.(50~90KPH, radious-100m)

Data aqusiton region is 20m

My task is get a specific region of data (9.9~1.1m)

I attemped to using on/off triggring but I couldn't find the answer..(it has not a input condition)


is it possible?


-Dasylab 9.0 : Tool
-Iotech Daq book 100 : DAQ board

-accelerometer : accelation

-VBOX(recelogic) : velocity

 

 

seohojin
Member
Tiger진
Posts: 4
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Re: How to stop and restart a measurement with a specific criteria?

missed attach..

 

seohojin