Subject: Humidity sensor in explosive environment

From: Craig van der Walt <[email-masked]>
Date: 9 Oct 1995 15:34:41 GMT

Hi I am looking for a method of measuring the humidty and temperature in 
a large wine cellar.  The cellar is classified as Class 1 division 2.

I will be connecting to a PLC and require an issolated 4-20mA signal

The humidity will be in the range 40 - 80 % and the temperature in the 
range 0 - 30 degrees centigrade.  The ADC converter has a 10 bit 
resolution.

Can anybody recommend which type of sensors to use.  I would aslo like to 
know the difference bettween an issolated and non issolated sensor.  
Would it be better to use an explosion proof sensor or just place the 
sensor in a

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From: Craig van der Walt <[email-masked]>
Date: 9 Oct 1995 15:39:28 GMT

Hi sorry hit wrong key on original post.  Here is the complete question :

Can anybody recommend which type of sensors to use.  I would aslo like to 
know the difference bettween an issolated and non issolated sensor.  
Would it be better to use an explosion proof sensor or just place the 
sensor in an intrinsiclly safe barrier.  

What type of sensor would be recomende for temperature measurement, PT100 
or thermocouple(I doubt this one will work).  Any leads would be 
appreciated.

Regards
Craig
[email-masked]

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From: Lew Harriman <[email-masked]>
Date: 9 Oct 1995 20:08:40 GMT

Craig,

You might try Hy-Cal Engineering. They make an industrial-grade 
temperature and humidity sensor/transmitter, which their literature says 
is Factory Mutual-approved for service in Class I, Division I, Groups 
B,C D and Class II, Division I, Groups E, F and G. (I'll bet it doesn't 
come cheap!)

My catalog says HY-CAL is located in El Monte, CA (818) 444-4000

Hope this helps,

Lew Harriman
Mason-Grant

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From: [email-masked] (paul milligan)
Date: 9 Oct 1995 16:06:04 GMT

In article <[email-masked]>,
   Craig van der Walt <[email-masked]> wrote:

~~>Hi I am looking for a method of measuring the humidty and temperature in 
~~>a large wine cellar.  The cellar is classified as Class 1 division 2.

~~>Can anybody recommend which type of sensors to use.  

	Pneumatic  :~)

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