scan rate

[s.joshi@pondbiofuels.com]

Morning Everyone.

I am trying to write data from 4 channels and time stamp into a single excel sheet using TDMS function. Initially I had all the logic in one single while loop but that slowled down my DAQ, the data used to get refreshed after every 40/60 sec. My process needs very fast scan rate( 1 sample per sec) so I tried to make a while loop just for my DAQ, so that it will always keep on scanning it. I am using local varibale to trasmit the data outside the while loop. Still I am facing the same problem. I have attached my VI.

Can you suggest any solution?

Thanks 

[crossrulz]

Why do you have a loop inside of another loop?  They need to run in parallel.  Further, you should loop at the Producer/Consumer architecture.  The idea is to use a queue to pass your data from one loop (the data read) to the other loop (the data logger).  This allows for all data to get logged properly.

[Hatef.fouladi]

I do not think your daq couse such delay but your answer is using Producer &Consumer methods so use queate for this one 

the attached vi will be help you 

[s.joshi@pondbiofuels.com]

Thank you all for your advice I will try to implement it.

Cheers.

[s.joshi@pondbiofuels.com]

Hi everyone.

 I tried the Procedure /csutomer method, please refer to the VI, still my scan rate to display the reading is very less. I though the sensor is the problem so I created a VI with just the DAQ and display chart, I was able to see instatenious changes in the graph. I am not sure what I am missing here.

Much appreciate it.

Thanks again

[Hatef.fouladi]

As I told you before you delay problem is not relate to your daq i think you have problem with setting appropriate sample to read for getting faster cycle for your loop 

[s.joshi@pondbiofuels.com]

Thanks for your reply Hatef.

I don't have much experience in Labview would it be possible for you to suggest me  waysthrough which  I can increase the scan rate for my while loop. I tried  sampling the data but it didnt help.

Thanks 

[Hatef.fouladi]

could you give me some information of your daq cart your vi do not work and is broken because some of subvi are not exists and you have to resend them too 

[s.joshi@pondbiofuels.com]

Thanks for the quick reply Hatef.

I am using Vernier Labquest mini as a DAQ( Initially I was using two DAQ Labquest mini and Sensor DAQ, which had in total of 7 sensors which made the loop slower so for now I am just using 1 DAQ, Labquest mini with 3 PH sensor). Please find attached VI I have tried to put everything together.

Much appreciate it.

[stevem181]

Attached is a modification of your code.

I don't have the Vernier LabVIEW software, so I put in a way to simulate it's operation.

A front panel control allows you to select Simulate or Real Hardware.

(Note: you will need to remove the disable structure on your Express VI - or just enable it.)

When you exit the program using the Stop button, a TDMS Viewer is started (selectable on the block diagram).

steve