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Old December 1st, 2009, 06:36 AM   #1
gwe4
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Zelio Logic Analogue Temperature Input

I have an SR3 24v. DC Zelio Logic Relay. I do not understand how to get temperature inputs. I have a few quetions. Do I need to use an analogue converter? I am trying to measure air temperature in a greenhouse. I need to measure in the -40 to 40 or 0-100 degree C. range. If I do need a converter and I get one that has one of the above temperature ranges does the temp. range of the probe need to be an exact match to the converter? For example, could I use a probe with a 0-500 degree range with a converter that has a 0-100 degree range? Thank You
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Old December 1st, 2009, 06:56 AM   #2
O_P
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Quote:
Originally Posted by gwe4 View Post
I have an SR3 24v. DC Zelio Logic Relay. I do not understand how to get temperature inputs. I have a few quetions. Do I need to use an analogue converter? I am trying to measure air temperature in a greenhouse. I need to measure in the -40 to 40 or 0-100 degree C. range. If I do need a converter and I get one that has one of the above temperature ranges does the temp. range of the probe need to be an exact match to the converter? For example, could I use a probe with a 0-500 degree range with a converter that has a 0-100 degree range? Thank You
I'm not really sure what u are asking for... But the analogue inputs are 0-10 V, so u need an signal converter. It also sounds as if u are using PT-100 probe for measureing. There are some PT-100 probes with transmitters/converters to 4-20mA built in the head of the PT-100 probe. So u might need a 4-20mA - 0-10V converter... BUT this is just what ia think, if u would like a better answere u have to tell us about hardware and such.

//OP
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Old December 1st, 2009, 11:37 AM   #3
milldrone
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Quote:
Originally Posted by gwe4 View Post
Do I need to use an analogue converter?
Yes. You will need some sort of temperature to analog conversion.

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Originally Posted by gwe4 View Post
I need to measure in the -40 to 40 or 0-100 degree C. range.
Here is a suggestion for a probe and transmitter (converter) in one unit
http://www.automationdirect.com/adc/...25C-20-0100C-H

You will also need a resistor to change the 4 to 20ma. output to a 2 to 10 volt signal. Yes you will also loose some resolution here also.

I have attached a pic from the zelio manual showing a temperature control scheme. With a 0 to 100 degree C range you will have only 100 points of resolution. 80 points if you use the transmitter I suggested.

If you decided to ditch the Zelio and use one of these.
http://www.automationdirect.com/adc/Shopping/Catalog/Programmable_Controllers/CLICK_Series_PLCs_(Stackable_Micro_Brick)/PLC_Units/C0-02DD2-D
You would have 4096 points of resolution. The software is free and they have good phone support.
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File Type: jpg zsample.jpg (41.8 KB, 98 views)
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Old January 16th, 2010, 05:34 PM   #4
skweak
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Zelio Temp Input

Hi, I am dealing with a similar situation, I am wanting to hookup a 10K temp probe to an analog input, but I was wondering can I just put the probe directly across the input? or does it need a current limiting resistor?
I have a SR3B261BD Zelio (24V DC) and I am using FBD programming.
The Zelio is operating my pop up sprinklers which are split into 5 zones for watering, and operate 24VDC solenoids, and it also runs the home ventilation system, which is pretty basic at the moment and I want to change it around.

Can I also have some help with the programming?
I know how to set an analog input in Zeliosoft, but can I just feed the input result directly into a comparitor and make a decision based upon that?

What im wanting to do is fairly simple, so im sure someone out there has accomplished what seems to be a bit of a mission for me!!

Thanks in advance

Andrew
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Old January 17th, 2010, 08:09 AM   #5
chud
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as said before, the zelio analogue input is 0-10V.Use the suggestions mentioned above or get a convertor from schneider that converts pt100 signal to 0-10V. Cant remember the part number .You get 8 bit resolution which should be more than enough for a project at your house where precision is not a major issue. And yes just link the input to a comparator and work from there. The comparator will work from 0-255 (8bit resolution)
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Old January 17th, 2010, 12:52 PM   #6
skweak
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as said before, the zelio analogue input is 0-10V.Use the suggestions mentioned above or get a convertor from schneider that converts pt100 signal to 0-10V. Cant remember the part number .You get 8 bit resolution which should be more than enough for a project at your house where precision is not a major issue. And yes just link the input to a comparator and work from there. The comparator will work from 0-255 (8bit resolution)
This is the first time I have played with analog inputs, so my solution is very crude, but seems to work well for my application. I made up a voltage divider, using a 20K resistor and a 10K Thermistor, and put it across the 24v supply, which gave me a variable input of 0-10v to use for the input (Between the 2 resistors). As precision is not really important, I was able to feed these values into a gain, give them some setpoints and feed them into a comparitor, and boolean table to achieve what I wanted to do. It still needs some tweaking to smooth a few things out, but overall I think I can sort it out!
I am also keen to know if anyone has used the data logging features of this model of zelio (SR3261BD) In FBD there are ARCHIVE, SLIN & SLOUT, does anyone know if these can be used to write data to a memory, maybe an analog input value every hour? to a memory, and then are able to download it using the USB cable?
Would be interested to know if there is already a post for this, or if I could PM with someone to work it out (if Possible)

Cheers

Last edited by skweak; January 17th, 2010 at 12:56 PM. Reason: forgot to add some stuff!
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