Humidity monitor

[jiqiu]

HI,

Right now I am have a thermocouple module SCXI 1102 and terminal 1303. I am wondering if I can use this module to monitor humidity since SCXI 1102 can also acquire volt input. I have not buy any humidity sensor or transducer. Do you have any experience on this, and can you recommend some humidity transducer? BTW, the humidity range is between 45% to 65%, no high accuracy requirements. Thanks.

[Kameralina]

Hello,

You should be able to use the SCXI-1102 for your humidity readings without any problem.  You will need to ensure that the range of the voltage generated by the humidity sensor that you choose matches the voltage range of the SCXI-1102 module. 

Also, you should be aware of the correlation between the voltage acquired and the humidity.  This correlation (should be specified by the manufacturer of the sensor) should be handled by the use of Custom Scales in MAX.  We don't have any humidity sensors that are NI recommended, but you can search on Google to find a multitude of sensors.

If you are able to find a TEDS sensor for humidity, then the scale will be imported automatically.  I was not able to find such a sensor during my search on Google, but a more thorough search may find you one. 

I hope this helps.  Please let me know!

[jiqiu]

Thanks.

I will get a Elektronic humidity/temperature transmitter EE08 series.

supply voltage: 4.5-15Vdc,

output1: 0-1 vdc over 0-100%RH,

output2: 0-1 vdc over -40-80 C ( -40-176F)

1. Could I use it to monitor temp and humidity at the same time with SCXI 1102? I think the output voltage is similar. (humidity range 45-65% , temp range 45-60F)

2. Could i use it on SCXI 1520 for humidity monitoring? I saw the ariticle on http://forums.ni.com/ni/board/message?board.id=300&message.id=2298&query.id=63564, which said we could but had some troubles. If I can , could i still use that module (I have 8 channels there) to monitor strain gage readings?

Thanks again for your assistance.

[Kameralina]

Looking at humidty sensors and at the one you chose, it seems that it requires excitation, which the SCXI-1102 cannot provide.  The SCXI-1102 is a thermocouple (passive sensor) module. 

By refering to this article from SensorMag you should be able to get some more info on how to choose a humidity sensor.

It seems as though the other user used the SCXI 1520 because it could provide excitation for his Elektronik RH sensor.  He was able to get his setup functioning so you should be able to acquire from the SCXI-1520 successfully as well.  You can use the other channels for strain readings if you want to. 

When I looked it up, I found that the Elektronik EE08 series takes a supply voltage of 7 - 30 VDC, and the SCXI-1520 can supply upto 10 V (within the sensor's range), so that should be fine for your application.

I hope that this answers your questions!

[jiqiu]

Sorry, i am not clear in my last question.

Yes, I am going to offer extra power source for the EE08 sensor. With that, can I monitor the RH and temp at the same time with SCXI 1102?

I have SCXI 1502 with my DA right now, and it has 8 channels there. I am a little worried about that if I use one channel to monitor RH, it will disturb other channels' readings for strain gage, isn't it? That's why I want to try the thermocouple (1102) to monitor the RH and temp, so i do not have to sacrifice one 1502 module to only monitor RH.

Thanks.

[Kameralina]

Hello,

I believe you should be able to read both with the SCXI-1002, but I am not very clear on how the two output wires transmit the temperature/humidity data.  Is it differential output, or is it one wire for each measurement?  If you could provide this information to me (I was not able to find it), then I would be able to better answer your question.

As for the other module, the SCXI 1520 (I am assuming that the 1502 that you just asked about is a typo) has settings for gain, excitation, and filtering that are programmable PER channel.  This means that using one channel for your humidity sensor, should not affect the other channels, and that you will still be able to use them for strain gauge measurements if you want.   This is in fact the answer that you were hoping for. 

Have a great day!

[jiqiu]

  Hi,

That would be great if the channels on SCXI 1520 would not influence each other.

Yes, this transducer has two outputs, one is for temp, and the other is for RH, both of them have the output range 0-1 vdc. I attached a drawing for their connection and its specification file.

I am still going to try use thermocouple SCXI 1102 first, I think it is the safe way and no interfere at all.

Thanks.

[Srinithi]

Sir/Madam,

Kindly help me with the building of the block diagram to monitor the temperature and relative humidity in labVIEW.

Thank You.

[altenbach]

(You are responding to a 5+ year old thread here...)

Please provide more information. LabVIEW cannot measure anything directly, you need some kind of sensors or other hardware. What kind of IO hardware do you have for temperature and humidity?

[Srinithi]

Sir,

I'm are going to use LM35 sensor for temperature monitoring and sy hs220 sensor for relative humidity monitoring.

It will be helpful if you provide with the required blockdiagrams for implementation.