Measuring Humidity in Soil

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Thread Starter

Steven

I need to measure the humidity in a composter. If the composter is 1m in height, can i measure the average humidity in the container? The problem is water will tend to be at the bottom of the container. Can anyone out there help out?

This is part of my Final Project for my
course in Mechatronics Engineering in Diploma Level. I intend to use a PLC to get all the data from the sensors and then the machine can do something about it. That goes to another part of the project...
 
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Gilles Habel

One of our customer used a measuring kit from Vaisala (www.vaisala.com). I make it communicate via RS-485 with Schneider Premium and Micro
PLC's.
I don't have any clue about the quality of those products but I know that they can talk to those PLC's...

Gilles Habel
Schneider Electric (Canada)
 
Thanks for your advice. Pardon me for asking, what is RS-485 and Schneider Premium? It's the different brands of PLCs right? I'm new to PLCs and I'm trying to learn it now. Does it matter if we use different types of PLCs? The website you gave me really helped out a lot.
 
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Clark Southoff

Steven:
There are several humidity sensors that can be interfaced to a PLC. Do a web check for them. Application notes from Linear Technologies have interfacing notes for a humidity sensor. The output is frequency. The other option is to use a dielectric type sensor, a home made capacitor.
-| |- cover the exposed metal with Kapton tape.
The material in between can be compost.
It can be used with a 555 timer configured as an astable mode.

The change in humidity will be some what non linear yet usable.

The other method is differential thermal measuring the time an area take to heat up and cool down, inferred that the compost has a higher heat capacity> humidity.

or some one else has a ready made solution off the shelf
Best regards
Clark Southoff
Technology Wranglers Inc.
Calgary, Alberta, Canada
 
Thank you very much Mr. Clark. That had helped out a lot especially to a person who is new to
PLC. There are a few questions. Are sensors readily made to produce signals for measuring
purposes? And the signals usually transmitted are in the form of voltages, currents and
frequencies? Am I correct? The PLC will be able to receive these signals provided they are
manufactured for the purpose, is that correct? That's all for the moment.
 
Regarding the suggestion you gave 2 months ago, I would like to ask you whether my interpretation is correct or not. This is what you wrote:

> Steven:
> There are several humidity sensors that can be interfaced to a PLC. Do a web check for them. Application notes from Linear Technologies
have interfacing notes for a humidity sensor. The output is frequency. The other option is to use a dielectric type sensor, a home made
capacitor.
> -| |- cover the exposed metal with Kapton tape.
> The material in between can be compost.
> It can be used with a 555 timer configured as an astable mode.

how is it that the exposed metal is to be covered with Kapton tape. Is it the metal of the compost bin if that's what you mean by the
material in (between the metal) can be compost. I can't seem to find the site to read about the interfacing notes for a humidity sensor. Do
you still have the address with you?

Thank you!

Steven
 
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