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edsel456
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WSN 3202: increase sensor power delay before reading?

On an NI WSN-3202, Is there any way to increase the time between activation of sensor power and the time an analog reading is taken?  I presently have the devices set for 250ms, but I would like to have the power turned on a good 2-3 seconds before a reading is taken.  Is there any way to facilitate this, perhaps through a custom firmware update?

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Che_T.
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Re: WSN 3202: increase sensor power delay before reading?

Hi edsel456,

 

This can be accomplished by using a sequence structure.  The valid sensor power settings are 0ms, 25ms, 100ms, 250ms, Always On.  So, since we don't have 2-3 seconds, we'll have to perform a workaround.  You can set the property node of the sensor power to "Always on", then wait 2 or 3 seconds, take the sample, then set the sensor power back to "Always off" to conserve battery power.

 

 

Regards,

Che T.
Applications Engineer
National Instruments
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edsel456
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Re: WSN 3202: increase sensor power delay before reading?

Hi Che,

 

Thanks for the input.

 

I don't see an "Always Off" option in the enumerated constant that appears for Sensor Power.  How can I be sure the sensor power actually turns off when the node exits the sample state?  Should I just set it back to 0ms in the next frame of the sequence?

 

Thanks,

-Mat

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Che_T.
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Re: WSN 3202: increase sensor power delay before reading?

Hi Mat,

 

It may depend on the node.  Whenever I do it on my WSN 3202, it does not have a Sensor Power property available.  However, on my WSN 3226, the property is available with the enumeration.  Can you post a screenshot of what you see?

 

 

Regards,

Che T.
Applications Engineer
National Instruments
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edsel456
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Re: WSN 3202: increase sensor power delay before reading?

Looks the same as yours, just no "Always off."  Screen shot attached.

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edsel456
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Re: WSN 3202: increase sensor power delay before reading?

Success!

 

The state machine shown in the attached screen shot does what I need.

 

Thanks for all the help.

 

-Mat

 

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Che_T.
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Re: WSN 3202: increase sensor power delay before reading?

Hi Mat,

 

Thank you for the update, and for posting what ended up being an acceptable solution for you.

 

 

Regards,

Che T.
Applications Engineer
National Instruments
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MaLac
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Re: WSN 3202: increase sensor power delay before reading?

Hi I tried to replicaded the same idea but with all 4 channels.

Does the sequence must be in the "sample" state ?

In the default sample state, there is no radio message, just links with shared variable. Do I need to add radio message for it to work ? For the moment, in the first frame I set power as always on, in the second I wait 2 seconds, in the third I put what was in the default sample state and in the last I set power as always off.

Once deployed to the node at the first sample it set the power sensor to always on, but remained in that state, it doesn't switch off the power.

For the moment I can't add a print screen since I wrote from another computer.

 

Thank you

 

Mathieu

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Aldo_A
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Re: WSN 3202: increase sensor power delay before reading?

Hi Mathieu,

 

The radio messages will make sure that you are sending your data back to your host. Please add them to your sequence structure and let us know if that fixed the issue for you. Thanks!

 

Aldo A
Applications Engineer
National Instruments
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MaLac
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Re: WSN 3202: increase sensor power delay before reading?

Hi,

Thank you for the reply.

I use a wsn-3226. There seems that there is no option to send data with radio message.

Here a print screen of my sequence, it is fairly simple, I don't understand why it's getting stuck in always on power.

 

I also tried to change the power setting with a user message and it worked. But it is unpracticable, I really need that to work. I use sensor that need to be power up at least 2 sec before sampling.

 

Thank you

 

Mathieu