Alternative for PID - Page 2

Need help with equipment usage or want to share your latest discovery?
baldheadracing

Postby baldheadracing » Dec 04, 2018, 12:39 pm

sandc wrote:.. who knows what is required on the legal side (UL marks and such) if a company exports to the US? ...

blondica73 wrote:It makes sense. However, I'm still surprised we don't have something similar in the US.

Testing by UL or similar is the responsibility of the importer/USA reseller or end-user; a kit could be exported to the USA by a company not in the USA. (The CE mark means nothing in the USA.)
OTOH, a product sold to consumers from within the USA pretty much has to be tested, and testing isn't trivial. One can almost predict how a Kickstarter of an electrical device will turn out when you see their timeline/budget for testing and certification.
What I'm interested in is my worst espresso being fantastic - James Hoffmann

blondica73

Postby blondica73 » Dec 04, 2018, 1:17 pm

baldheadracing wrote:OTOH, a product sold to consumers from within the USA pretty much has to be tested, and testing isn't trivial. One can almost predict how a Kickstarter of an electrical device will turn out when you see their timeline/budget for testing and certification.


Where could I find the OTOH board?

baldheadracing

Postby baldheadracing » replying to blondica73 » Dec 04, 2018, 1:43 pm

Sorry, too many Internet acronyms :oops: : OTOH = On The Other Hand
What I'm interested in is my worst espresso being fantastic - James Hoffmann

blondica73

Postby blondica73 » replying to baldheadracing » Dec 04, 2018, 2:00 pm

:D

I think the title of the post should change to "Alternative for PID - EU only"

sandc

Postby sandc » Dec 04, 2018, 3:05 pm

> Alternative for PID - EU only"

A bit more than the EU. Blue and orange areas in this map have 50Hz power. You can have it delivered anywhere if you use a service that provides you with an EU shipping address, like https://www.easy-delivery.com/en/ (not an endorsement, just one that popped up on Google). Parcel size is 23x20x9cm, weight less than 2kg.

blondica73

Postby blondica73 » Dec 04, 2018, 3:24 pm

Thank you sandc. Would you mind helping with what items I would need to order?
I am looking for the ito+pressure sensor+display.

sandc

Postby sandc » Dec 04, 2018, 5:03 pm

Please check the links at the bottom of this post, they pre-select components for specific usage cases. If you risk getting it for use with 110V/60hz, indicate that you require 2mm² leads for the 20A relay. For the special case of a Vivaldi, in which only a fraction of leva!'s features can be used (if the original controller is retained as primary controller), you might want to run this thread through Google translate. For controller-less machines (Silvia etc), the latter parts of these threads might be interesting: thread 1, thread 2.

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Chert

Postby Chert » Dec 04, 2018, 5:16 pm

Very interesting.

Sounds too easy, like I might actually be able to implement it.

I am cobbling together a 220/240 volt machine and it has a rotary pump.

Is there a similar solution for rotary pumps?
Abolish single use plastics.

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radudanutco

Postby radudanutco » Dec 04, 2018, 5:36 pm

@sandc:
I am in EU, and I am quite interested in your kit!
(late edit: I shall read the links in your above post #17)
what I have to decide - I hope with your help - is, if there is and what would be a configuration suitable for my case!
perhaps you can provide me with an contact address/link, for posting some more details, as I am afraid my request does not fit your firmware... perhaps I don't even need the firmware...

however, trying to be short:

it is about a modified Strega: I use a PID for controlling group temperature (effective mostly in idle), a pressure gauge conveniently connected after the check valve and the ULKA EX5 pump, and a standard light/fan switchable dimmer to control the average flowrate of the pump;

you know, the Strega is using the pump for filling the cylinder chamber via an heat exchanger: with a stock machine, there are 5 sec of 0 bar chamber filling (at maximum pump flow rate of more than 10 ml/sec), then the pressure starts to build up, the flowrate is diminishing and somewhere on the pressure ramp (to 10 bar) the puck will became saturated and the extraction will start to flow into the cup;
at this very moment of the preinfusion ending, the lever is usually raised, manually, 'on the springs' and the extraction continues under the pressure of the springs;
as soon as the lever is leaving its lower resting position (piston is coming down), a microswitch disconnects the pump and from now on the process is fully manual/mechanical;

the preinfusion lasts usually during the pump run, and it is this phase of the shot only, when I need the right control of the pump flow; it could be a manual control, with a knob, or also a programmatic one;

for using this phase of the process to profile the preinfusion, your way of controlling the pump seems the best!
however, I wonder if you have any pressure-flowrate chart for different settings in controlling the pump?
would it be possible with a vibratory pump to have a complete pressure ramp up to 10 bar (the pressure exerted by the springs after), but with a slower flow, which would make this ramp much longer?

with a standard dimmer in its lower setting, in my case, the pump runs slowly, reaching a maximum of 1-1,5 bar in the chamber, in more then 25 sec; and the pump 'dies' - zero flow;
this means a lower volume of water into the chamber and a lower starting pressure for the springs; it would be better of course to be able to experiment further...

also I would like to use both PID functions, for the group and for the boiler too; and the better sensor and sampling provided;

I wouldn't like to use a dedicated screen if all display functionality could be transferred remotely to a laptop; but I presume it is possible to record all the real time charts, having kind of a data logger functionality?

I saw you have a deadline on Dec 7, so I would like to make an order before...
thank you sandc, for all the information!

sandc

Postby sandc » Dec 04, 2018, 7:14 pm

A lever machine with heat exchanger is miles beyond what leva! is designed for. It's for machines with vibratory pump, water straight from the PID-controlled boiler and preferably not with E61 group (examples: Rancilio Silvia, Bezzera BZ09, ...).

> there are 5 sec of 0 bar chamber filling (at maximum pump flow rate of more than 10 ml/sec), then the pressure starts to build up

That seems similar to a Silvia: A long and shallow pressure rise (e.g. up to 0,7bar over 6s) and then the pressure jumps up almost instantly (e.g. to 9bar in 1-2s). With leva!'s pressure control, this jump can be edited. It can, for example, be turned into a very slow rise. But you must have a pressure sensor for that.

> wonder if you have any pressure-flowrate chart for different settings in controlling the pump?

The pressure-flow relationship (the amount of water that the pump can inject into the system at a certain pressure) changes whenever the phase angle is changed. leva! has a control loop with feedback which adjusts the pump power as needed and iteratively. Using a chart wouldn't work. A sensor is essential.