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Vacuum sensor?

I would like to try a vacuum sensor on an Mport.
The problem is I have know clue what I'm looking for.

If possible I would like mfi to graph a log of the vacuum levels when I'm milking the cows.
Typical levels are around 13 to 14 Lbs when milking.
I need to see how high and low the fluctuation is.
Possible?
Thanks
Allan
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Re: Vacuum sensor?

It seems to me that the mPort serial controller combined with a serial pressure sensor and some programming would certainly be able to accomplish this. But, if you can run wires, mPort would not be needed. You could go straight from the sensor to an RS232 port on a PC.
However, I suspect that there already exists a more integrated/streamlined solution. How much would you like to pa Alfa Laval?
Edit: The network centric nature of UBNT made me think that something like MRTG or Cacti could also be used to graph your pressure reading. But, the weather community probably has a lot of software for recording/graphing barometric pressure that could likely be used as well.
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Re: Vacuum sensor?

It seems to me that the mPort serial controller combined with a serial pressure sensor and some programming would certainly be able to accomplish this. But, if you can run wires, mPort would not be needed. You could go straight from the sensor to an RS232 port on a PC.
However, I suspect that there already exists a more integrated/streamlined solution. How much would you like to pa Alfa Laval?
Edit: The network centric nature of UBNT made me think that something like MRTG or Cacti could also be used to graph your pressure reading. But, the weather community probably has a lot of software for recording/graphing barometric pressure that could likely be used as well.

You don't even need an mport serial for this, just use the terminal block. It can take up to 24v input. You just define a custom sensor type and it will graph it automatically. You can also set it up to email/text/run a script/send an alert/etc once it gets above/below a certain set point.
wiki.ubnt.com/MFi-Custom_Sensors


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Re: Vacuum sensor?

You want to go with something industrial grade for this most likely.

Something from mcmaster carr would probably work just fine, I use them for sensors/tools/parts all the time.

Example: www.mcmaster.com/#pressure-transducers/=jini7m


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Re: Vacuum sensor?

Thanks Guys
First off I throw enough coin at alfa laval. LOL
The grade is not to important as long as it works. The price is how ever very important.
I can't spend 400 or so on a sensor.
100 bucks is more my style. For that I could stick an aircam 12" from the gauge I have on the line now and have it record full time on a schedule.
I'll keep digging on the net for something in my price range.
Thanks again
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Re: Vacuum sensor?

I assume this is fluid and not gas? What range do you need to cover? Vacuum only, or does it need to read positive pressure as well?
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Re: Vacuum sensor?

Air vacuum . For a dairy milking system.
13.7 Lbs negative, Except when the controller farts and it goes up to 15 or more. And All my cows get Mastitis.
Vacuum only
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Re: Vacuum sensor?

A Dwyer 628-01 will do 0-30 PSIA, which should work for you.

www.dwyer-inst.com/configurator/index.cfm?id=35 will let you specify the other options. Those are list prices - distributors should do a bit better.
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Re: Vacuum sensor?

Air vacuum . For a dairy milking system.
13.7 Lbs negative, Except when the controller farts and it goes up to 15 or more. And All my cows get Mastitis.
Vacuum only


Speaking of mastitis, I recently saw National Geographic's Dr. Pol talking about a "spider" in a cows teat.

Icon Eek Icon Eek Icon Eek Icon Eek
National Geographic Video
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Re: Vacuum sensor?

www.automationdirect.com/static/manuals/prosense/prosense_ptd25_installation.pdf
Note the link is a PDF
Was just looking at this one .
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Re: Vacuum sensor?

Was just looking at this one .


Only 14.5 PSIA, or do they make one with a wider range?
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Re: Vacuum sensor?

Only 14.5 PSIA, or do they make one with a wider range?


I dunno I found one of those on fleabay for 15 bucks ! I can afford to test at that price.
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Re: Vacuum sensor?

I bought this one cgi.ebay.ca/ws/eBayISAPI.dll?ViewItem&item=330799571007&fromMakeTrack=true&ssPageName=VIP:watchlink:...
The range is not huge yes, but the system is regulated at 13.7 roughly , except when the regulator malfunctions. Then there is a chance it will spike over 14.
Here is a link to the instructions for this sensor www.automationdirect.com/static/manuals/prosense/prosense_ptd25_installation.pdf
I want to ask the Ubnt team how they recommend wiring it to the mport in case I blow 1 or both up!!
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Re: Vacuum sensor?

Below is my sensor specks
Operating voltage ............................16 to 32 DC1)
Current consumption ...................................< 18
Analog output...........................................0 to 10 V DC
Load ....................................................min. 2000
Step response time analog output .....................3

Output is 0 too 10 Vdc
So according to the ColliHigh Illuminometer example on this page wiki.ubnt.com/MFi-Custom_Sensors
Would I just double the 33Kohm resistor or would I have to lower the 22Kohm resistor value as well?
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Re: Vacuum sensor?

In the custom.json file sensor definition "conversion "
I see these examples.
"conversion" : "xyz*5000",
"conversion" : "-31.11+xyz*55.55",
"conversion" : "xyz*100",
"conversion" : "xyz*8.5",
Can someone explain the xyz and the values, what exactly do they mean. Is there a table somewhere or does one simply pull these out of thin air?
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