continuously reading two sensors (alternatively) in an event structure

[grega]

Hello,

I have an event structure with various functions from user interface. The whole application is about controlling a laser diode and reading two IR light sensors which cover different wavelengths (Si and InGaAs). Both sensors are connected to the same AD converter, but to different channels. So if I want to read from both sensors I have to change the channel setting on AD converter. The real question is how to implement countinuous reading of both sensors in the event structure? I want to be able to read alternatively each sensor in a timespan of 50 or 100 ms. Is there any way, other than using timeout function of the event structure with some kind of xor logic for switching the channels? Maybe something with more functionality (somehow by a timed loop)?

Any idea is welcome.

Thanks and Regards,

Gregor Primc

P.s. The sensor reading is done by a National Instruments SPI card where SPI is the master.

[AB@17]

This VI may solve your requirement,if this VI is once fired by user event from Front Panel,it will start alternatively firing with out any user event

You can use this type of logic to implement your acquisition

[grega]

Hey,

thanks I will check it out. Could you post the vi in 2010 or 2011 version? I have version 11.0f1...

Regards,

Gregor Primc

[AB@17 · Accepted solution]

2010 down converted VI

[crossrulz]

If you are constantly reading, I would recommend making a separate loop for the reading.  You can easily then change which sensor you are reading whenver you want.  You will need to setup some type of communication between the loops using queues/notifiers and events.

[grega]

Hey,

thanks for the solutions. However I have another question. What would be the best way to do a reading for 3 different sensors (from the same AD, different channels) every 50 ms for each sensor, and reading another sensor (temperature, which is also on the same AD, but different channel) each 200 ms.

- do you propose two loops with events, where in one loop in enqueue different reading tasks for each sensor (how can incorporate different time scales)

- or maybe only queues with case structure

- or maybe some form of timed loop?

Thank,

Grega