Your suggestions on a special project.

Hi guys,
             I would like to know your opinion on a project that I wish to begin this september.  I want to monitor 5 vacuum lines with the webcontrol board. Each vacuum lines are at 1 km from each other. So I'm planning to use more than 1 board.
 
I found my vacuum sensor : ( MPXV6115VC6U )
 
http://www.digikey.ca/product-detail/en/MPXV6115VC6U/MPXV6115VC6U-ND/951851
 
The question is how could I use more than one board and merge data in a mini webserver and have an ethernet display of the data.?? Is it possible to use board as slave/master
 
Is it a good idea to use something like a Raspeberry PI #B. as a webserver??
 
An other question is : How do I calibrate the vac sensor with the analog input from the board??? 
(ex : - 5 psi = ''236'' analog value.) Then ''236'' should display -5psi in my screen.
 
 
Please give me ideas!
 
Any helps will be appreciate!
 
Thx
 
 
 

Should iI use Arduino instead of CAI Network Webcontrol ?

Use whatever you are most comfortable with.  Yes a linux based system like RPi would be good for the main server. 
 
What are you doing working at the LHC?  ^_^

I have used the freescale pressure transducers with webcontrol boards quite a bit.
 
If your measuring stations are 1km apart you will obviously need a separate board for each location.
 
The "webset" function on the cai boards is designed to sync together multiple boards.  So if you need to have all the values on one board for some logic function, then this will do the trick.
 
I am not familiar with raspberry pi except that I know what it is.  I have never used one.
 
The freescale transducers use 5v which can be provided by the webcontrol board.  They return .2 to 4.7 volts which is linearly related to the pressure.  They have some error.  In my experience it can be plus or minus .1v, however it is not a random error.  For example, a .1v high device will be .1v high pretty much at all pressures.  So they can be calibrated in your software.  The CAI board reads 0 to 5 volts as 0 to 512.  CAI's built-in PLC code can easily do the math to convert the raw number into PSI or whatever and store it as a variable for your viewing pleasure.  Cai may have some noise of maybe plus/minus 1 or 2 (.01 or .02 volts), so you mar or may not need to use some noise buffering caps if this level of precision is an issue.
 
What exactly are you trying to do with the data?  Are you just viewing the values. .. basically remote gauges. .. . or are you implementing some automatic control function?  Reading the data does not require a server.  A simple application on a pc can query the boards over the internet and plug the values into a nice display.  Or you can just use the webcontrol's built-in webpage to view the values if it doesn't need to have a custom appearance.

HI,
      First, thanks for support. 
 
 
''The "webset" function on the cai boards is designed to sync together multiple boards.'' 
 
How much board exactly? How should do I porcess to merge all data on the board? 
 
 
 
''AI's built-in PLC code can easily do the math to convert the raw number into PSI or whatever and store it as a variable for your viewing pleasure.''
 
Okay so with a simple PLC code I will be able to convert the value ''156'' to the appropriate psi value?...
 
 
 
''What exactly are you trying to do with the data? ''
 
First of all it will be a remote gauge. Maybe log the data into files only if it's not too hard for me. (I'm a beginner) And I willcertainly use it in my plc prog to do some automatic control function.                              
 
 
 
People here are very friendly and give a lot of support! I like it ! thx a lot we can grow up!!!!!

BTCAD said:

HI,
      First, thanks for support. 
 
 
''The "webset" function on the cai boards is designed to sync together multiple boards.'' 
 
How much board exactly? How should do I porcess to merge all data on the board? 
 
 
 
''AI's built-in PLC code can easily do the math to convert the raw number into PSI or whatever and store it as a variable for your viewing pleasure.''
 
Okay so with a simple PLC code I will be able to convert the value ''156'' to the appropriate psi value?...
 
 
 
''What exactly are you trying to do with the data? ''
 
First of all it will be a remote gauge. Maybe log the data into files only if it's not too hard for me. (I'm a beginner) And I willcertainly use it in my plc prog to do some automatic control function.                              
 
 
 
People here are very friendly and give a lot of support! I like it ! thx a lot we can grow up!!!!!

Click to expand...

 
There are 8 webset functions on each board, but it would seem that you would only need one since each board will only have one transducer value to report.  Each board has 8 variables which can be set by WEBSET.  Basically, webset lets one board set a variable on another board.  So if you had 5 boards, four of them would be used to set variables on the 5th board, thus all values would reside on one board allowing for any comparisons or whatever you want to make control decisions.  That board could then send commands back to the other boards to set variables on those boards or turn outputs on/off.  The PLC code might be written such that each board converts the analog input from the transducer into a psi and saves it as a variable.  Then it posts that variable to the other board.  Each board would send the value as per your instructions, like if it changes or every so many seconds or something.
 
Yes, it would be trivial to have the webcontrol board convert 156 into a psi.  Since it is a linear relationship, it would be a simple matter of multiplying the analog input times a conversion factor.  I would suggest figuring that conversion factor experimentally since each freescale transducer is enough different to warrant it.  

''Yes, it would be trivial to have the webcontrol board convert 156 into a psi.  Since it is a linear relationship, it would be a simple matter of multiplying the analog input times a conversion factor.  I would suggest figuring that conversion factor experimentally since each freescale transducer is enough different to warrant it.  ''
 
Okay I understand
 
 
How should I process to merge the 3 different boards inputs value in the same webpage using WEBSET VAR ??
 
 
 
thx a lot

Your description of what you are doing is far too vague for me to have any idea what the best way for you to do it is.
 
You could have each board post a value to one "master" webcontrol board.  You could have each webcontrol board post directly to a separate server.  You could have a server query the webcontrol boards.  I have no idea what sort of automatic control functions you are interested in and what sort of GUI the end user requires.  Also if the user is going to have some input as to what happens.  I really just have no idea what you are trying to do.

Haha sorry.
 
My goal is to have a webpage with all of my sensors display. I want to monitor the vacuum line in a maple sirup farm. There are few vacuum line in the forest that sometime reach some km.
 
 
The display screen should look like something basic for the begining.
Such as :
 
 
Sensor 1 : -10psi
Sensor 2 : -9psi
Sensor 3 : 0psi
Sensor 4 : 0psi
Sensor 5 : 0psi
Sensor 6 : 0psi
Sensor 7 : -2psi
Sensor 8 :-12psi
Sensor 9 : -7psi
Sensor 10 : -3psi
 
 
Each vacuum line have 1 km from each other. In my first post I write that I have 3 vacuum lines but it was a simple exemple.10 vacuum line is the reality. 
 
 
 
 
I also want to be able to make PLC code in relation with those value.
 
 
I hope my explication is better. Let me know.
 
 
thx

Webcontrol only has 8 variables, so you would not be able to display all 8 values on a single webcontrol board.  
 
But that won't stop you from having the webcontrol boards from posting the values to a server or querying the values from the boards.

What are you doing for internet and power?

okay.
 
 
Run a long cat5e :rockon:
 
Seriously I'll run an optical fiber between each board/server.
For the power I don't know what will be the best way. Maybe run a 16/2 stranded cable. Input 48vdc and at the end of the cable, downgrade the vdc with a LM2596. Or by using a solar pannel with a battery. The fiber converter + the board will not consum a lot of ennergy.

Hmm.  That is a lot of wire & fiber.  Solar panels in the forest?  I would suggest you use something else like an arduino variant where you can put it into very low current sleep mode, maybe try some long range wireless modules, and some lead acid batteries.  Or cellular data if there is a tower on a hill somewhere nearby.

I would use solar and wireless internet.  I know it is a forest, but I bet you could find a spot, or mount it on a tall pole.  Your talking about miles of fiber/wire if there are 10 of these thing spread 1km apart each.  A small battery (like an alarm system battery) with a solar charger probably would be enough juice.  The cai uses very little electricity, the wireless internet would be more of an issue.  If you have line of sight back to a location where you can have wired internet, then you can do use the long distance focused antennas.  They can work for miles.  I just don't know the power consumption on them.  You could add a relay controlled by aci that powers on/off the wifi antenna (if you need to save the electiricity) and have it turn on the wifi, wait 10 seconds for a connection, then send the values, then shut down until next time.
 
A cellular subscription times 10 would add up real quick.

Cellular is too expensive monthly. I think Fiber is the best way in a forest. Wireless radios do not work fine in the forest and poles need to be too high from the ground. Batterys and a medium solar pannel should work fine.
 
As you said, CAI board don't use a lot of electricity and media converter the same. Or a long 16/2 copper