Picaxe Programmer Wanted

troyjcm

New Member
Hi,

I have a commercial brewery that uses a picaxe 40x2 to control it with 3 x 14m2 satelite picaxe chips that monitor the volume and tempterature of each of 3 tanks. the 14M2 chips serout to the main chip which then controls Solid State Relays etc. It has worked well for 6 years but we will be increasing the size of the plant at the beggining of next year.

I have MPX5010DP pressure transducers that measure the pressure inside stainess tubes that run up the side of the tanks like a sight glass to determine the depth of the liquid in the tanks.

I would like to put triclamp pressure sensors on the tanks instead as they are more reliable and less likely to get blocked etc. I don't have the time now as the business has grown to work out all the code etc for new parts of the brewery.

Is there anyone on here that can do some freelance work for me with code etc. I use upwork for other software and data projects so can use that for this as well for payment etc.

The brewery is Lister's Brewery in West Sussex.

Many thanks

Phil
 

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troyjcm

New Member
The upwork job posting is here

 

matchbox

Senior Member
I would like to put triclamp pressure sensors on the tanks instead as they are more reliable and less likely to get blocked etc.
In all my projects that use pressure transducers. I connect the sensor up to the measurement point via a Pitot tube. Which consists of clear vinyl tubing and two barbed threaded fittings.
This uses the air in the tube as a medium for measurement, rather than the fluid. Which prevents the sensors ever getting blocked.
 

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AllyCat

Senior Member
Hi,

Aren't Pitot tubes used to measure fluid Velocity, whilst it appears the OP requires to measure a fluid Level (via the pressure its height creates)?

However, I'm also concerned about the reference to "pressure in tubes that run up the the side of the tanks like a sight glass", in view of the comments by Bill Wann in post #20, para 2, of This Recent Thread. Does the (existing) sight glass work with a closed top and/or will the "air" be refreshed regularly? There is also this comment on page 5 of the NXP data sheet (which seems rather strange in view of the claimed applications):

"The MPxx5010G series pressure sensor operating characteristics, and internal reliability and qualification tests are based on use of dry air as the pressure media. Media, other than dry air, may have adverse effects on sensor performance and long-term reliability."

Cheers, Alan.
 

matchbox

Senior Member
Hi Alan, Yes 'technically' its not a Pitot. But the term seemed easier to explain it with. Being that the tube has a pressure sensor at the other end;)

Here is a picture of one of my installs. Both use the same clear vinyl tubing. Which are covered in (black) split conduit, to prevent UV degradation. One has been running for 3 years with no issues.

I have only used water as the fluid in my applications, that is very often muddy, with bio-matter etc. Its pressures do not exceed 4.5psi.

I have not found any issue with tube expansion/contraction, from -6c through to +38c, affecting measurement.

As a side note. The sensors I use are also designed to work with Oil, Fuel and Water.
I also use this sensor in direct contact with fresh water, in a variable speed water pump. It has been in operation from 2016. With no issue. And is held at 60psi most of the time.
 

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