PO4 Controller possible?

[ZaneTer]

That’s alright. Sorry for the lengthy explanation but it really has been condensed down to about as simply as I can explain it.

 

[ZaneTer]

Looks like you've formulated a plan. Time for prototyping.
Following along for the ride.

I'll jump in when I have something relevant to offer.

Unfortunately I will have to wait for another 6 months before I can build the prototype as I am still on a project in China.

 

[Sherman]

Accuracy:

I mentioned this because currently GHL have the top spot for dosers but I see their accuracy as horrendous. They use a beautiful stepper motor but it is both expensive and truly not the most accurate as I will explain.

I use a cheap amazon $5 peristaltic doser. My particular doser operates at 100ml/min

Here is the cool part. My controller operates at <1ms but for ease of use I run it at 1ms exactly. This means that I can reach per millisecond dosing.

100ml/min divided by 60000 milliseconds per minute equals 0.0017 ml/ms

I have to run my code for around 6ms or 6 cycles to be able to dose 1/100th of a millitre.

GHL dosers aren’t looking quite so good anymore at this point.


Cost:

I will not include the controller as it costs around the same as a profilux P4. Lets have some fun calculating this. We will do the calculation based upon adding 32 individually controlled dosing heads.

Siemens parts:
1 x 32 digital output card @ $250
32 x $3 interposing relays @ $96
32 x $5 dosing heads @ $160
12v power supply @ $40
Wiring @ $50
Time ?????
Total $544

GHL
8 x 4 head dosing slaves ($400 each)
Total $3200

It’s a funny world we live in when $550 system beats the hell out of a $3200 system.

As always please feel free to ask any questions or if you have any comments. I will always happily answer your questions to whatever you technical level may be.

Wow sound interesting.
But this need someone who now how to write program for the controller right.
And how to tap points from the hanna tester to the controller inputs.
Just wondering any PLC can do the same job.

Sori I not very good at programming

 

[Sherman]

Hope you start a thread here I will just follow along

 

[ZaneTer]

Wow sound interesting.
But this need someone who now how to write program for the controller right.
And how to tap points from the hanna tester to the controller inputs.
Just wondering any PLC can do the same job.

Sori I not very good at programming

Yes it does require someone with knowledge of Siemens controllers. I am a senior engineer for Siemens. Any decent PLC will also be able to do this regardless of manufacturer.

The hanna button is only there to make a point of contact between two metal strips. I can do the same thing with a relay that is powered by an output from my PLC. I simply don't apply any voltage to the contacts and instead solder them onto the two metal strips on the hanna instrument.

 

[Sherman]

Hi Zane Thank You for sharing.
Nice to know any PLC can do the job.
So you estimate how many input and output points we need.
The hanna button point I understand. We can connect that to a PLC and run by program.
What about the display?
We still use back the original hanna display or we can transfer to another bigger unit?

 

[ZaneTer]

I will need 7 digital outputs for:
1 x sample water pump
1 x waste water pump
1 x RO water for flush pump
1 x recirculation pump
1 x transfer from mix container to cuvette pump
1 x hanna button replacement
1 x doser for reagent

? number of digital inputs for the screen integration - this might be the hardest part but until i can get my hands on a secondhand hi-736 i wont know.

Does this help?

 

[ZaneTer]

I would like to know what the chemicals are in the reagent. I suspect it isnt a single chemical but rather a combination

 

[Sherman]

Unfortunately I will have to wait for another 6 months before I can build the prototype as I am still on a project in China.

Yes it does require someone with knowledge of Siemens controllers. I am a senior engineer for Siemens. Any decent PLC will also be able to do this regardless of manufacturer.

The hanna button is only there to make a point of contact between two metal strips. I can do the same thing with a relay that is powered by an output from my PLC. I simply don't apply any voltage to the contacts and instead solder them onto the two metal strips on the hanna instrument.

I will need 7 digital outputs for:
1 x sample water pump
1 x waste water pump
1 x RO water for flush pump
1 x recirculation pump
1 x transfer from mix container to cuvette pump
1 x hanna button replacement
1 x doser for reagent

? number of digital inputs for the screen integration - this might be the hardest part but until i can get my hands on a secondhand hi-736 i wont know.

Does this help?

Thank You for sharing the info

 

[Sherman]

I remember hanna the reagent has print on each package

 

[ZaneTer]

It does but it doesn’t state the chemical composition.

 

[Sherman]

I would like to know what the chemicals are in the reagent. I suspect it isnt a single chemical but rather a combination

It does but it doesn’t state the chemical composition.

Ok