DIY PID kits - who's done it? With what? How'd it go?

[nikko.the.scorpio]

Hi Folks,

Though many modern espresso machines come with a factory fitted PID many other well regarded entry level pro-sumer ones e.g Silvia, Gaggia Classic etc do not - and the consistent feedback is that fitting a PID is one of the most effective ways to improve the extraction quality from these. Traditionally essentially these same components have been sold in pre-configured kits at considerable price markups (~$300+) - though they still required the user fitting them anyway. BUT often these machines actual market value/worth is as much or close to the cost of these kits, which might make the expenditure on such a kit slightly illogical (IMHO anyway).

In several recent threads I've found that people ended up discussing PIDs and specifically very cost effective DIY PIDs that they'd either bought in kit form (generally comprising a digital PID controller box, an SSR (solid state relay) unit and a K-type thermocouple) or individually purchased the bits from Ebay etc. Hence though it takes a little more effort it does seem somewhat logical to me to get the base components and save 80-90% in total costs though with a little more leg work required.

SO.....I just wondered if anyone has fitted a DIY type PID either from a basic kit or from component they compiled themselves? If so, what did they use for components? The Rex C100 is a very common one that comes up but I've seen discussion saying it's unsuitable for many machines as it only has a 2A internal relay? But love to know what folks have used successfully. I think you're saving quite a bit of money as is so getting good quality parts and not just the cheapest ones isn't a big trade off.

Likewise what reference materials did folks refer to for the install, programming of the PID etc?

Discussions applying to any PID kits (even the more expensive commercial ones e.g Watlow) welcomed and any machines that they're installed into.

Much thanks in advance,

Nick

PS. As Ebay links are not allowed might I respectfully suggest quoting the item numbers (where you can) for any items you wish to reference. Thank you. :-)

[nicovington]

I bought a full Auber kit for around the $300 you mentioned and wished I had gone the DIY route to save the money.

I am a control systems engineer, there isn't much too these, but at the time I had the money and couldn't be bothered sitting down to order all the parts.

This nice thing about a premade kit is you get everything already cut to size and terminated.

Regarding programming the PID, I'm sure once you've settled on a controller you will be able to find someone else who has already got approximate parameters and you can fine tune from there, many have an auto setup function as well.

If you are handy with a soldering iron, I have previously found you can crack open the cheap PIDs, remove the relay and route the coil pins to the rear terminals and then hook this up to a SSR.obviously caution needs to be taken on these, in particular when doing any testing as these units often seem to usenon galvanically isolated power supplies.

Nic

[blend52]

yes, its a no brainer for the able DIY user.
PID & relay are cheap ($30), + a housing of your choice unless you install internally.
The biggest issues are ensuring the wiring modifications are done correctly and safely, and mounting the unit, and SSR securely.
Most modern PIDs have outputs for both the SSR ( low voltage) as well as a internal relay for the mains voltage.
I used the 7100 series "mini" PID, but there are many others.

there are also several threads on here for this ...
http://coffeesnobs.com.au/brewing-eq...id-silvia.html

[deegee]

Hi Nick. I bought cheap bits off Fleabay to install on my Gaggia Classic, but before I got around to installing it, I decided that the Classic also needed a pre-heater to get any real benefit from a PID.
While I was still working out how to do this, I got a chance to buy a Gaggia Factory 106 lever machine at the right price, and then a Pavoni Pro, so I still haven't installed either a pre-heater or a PID on the Classic.

I did a lot of research though, so I believe I can answer some of your questions.

First, there are few (if any) cheap PID's that have contacts capable of switching the current required by an espresso machine boiler. However most will have a low voltage output that can be used to trigger a 20 or 25 amp SSR, which does the actual on/off switching.

I chose a "Sestos D1S-VR-220" PID, which will accept mains power from 100 to 240volts 50 or 60 Hz. I picked it because the instructions seemed to be a bit less confusing than the two others I looked at. Also it has a 12v output across two terminals clearly labelled SSR.

The SSR is a "Fotek SSR-25 DA" which will accept an input of 3 to 32 VDC and will carry up to 25 amps at up to 380 volts.

The thermocouple I got is a K type rated 0 to 400° C with a one meter lead and a ring terminal sensor.
This seemed to me to be the easy way to attach the sensor to the Gaggia boiler, but I'm not sure about the Sylvia.
They come in various temperature ranges, lead lengths, and ring sizes. Search "K type thermocouple ring" on Fleabay.

The sticky - step by step guide to PID a Sylvia ( link above) is very detailed (maybe a bit too much so) and includes some advice on setting parameters albeit for a different make of PID.

[nikko.the.scorpio]

Wow great replies and info gents - REALLY appreciate them very much. Absolutely excellent information - thank you ever so much. :-)

[Dimal]

If you are handy with a soldering iron, I have previously found you can crack open the cheap PIDs, remove the relay and route the coil pins to the rear terminals and then hook this up to a SSR.obviously caution needs to be taken on these, in particular when doing any testing as these units often seem to use non galvanically isolated power supplies

Suitable opto-isolators are a dime a dozen these days and can be inserted to achieve adequate isolation without too much difficulty...

Mal.

[nikko.the.scorpio]

Again excellent replies guys.

RE: PID controller boxes: Are they all pretty much of a muchness? Seems the cheapest ones on the market are all Rex-C100 clones. However it appears you have to do some simple soldering/desoldering to make those usable. I'm not averse to that BUT I've also read that their build quality is quite variable - especially as they're so heavily copied etc. So is there a recommended model above that that works well?

In the guide the CD-101 is used and it's still able to be bought for around $30 - but not sure if it's dated or still the best choice. The Sestos referenced above is available for a tad more, there's also some XMT ones and also MyPin or similar in the same sort of price range - dunno if any of them are the 'best' choice or if it's whichever one is cheaper....?

RE: SSR: Just wondered there's a lot of 'kits' of components that include 40A SSR's rather than 25A. Obviously is overkill for the needs but it that a good or bad thing? e.g if at same price preferable to have the 40A SSR or 25A?

Thank you again for such trivial questions. :-)

[blend52]

Be aware that some of those PIDs are 12 volt DC input, which means you would need a suitable power supply to use them. That is an unnecessary complication.
Also many of them are single channel only, which is fine unless you want separate control of steam temp as well as brew water.
Search the 'bay for a XMT 7100 PID.
They are the smaller 1/32 DIN mini format, 240 v input, with SSR control output ( 8 volts) as well as a 240 volt relay and are usually about $25 post free. No soldering needed !
infact the internal 240 volt relay on mine was rated for 7amps, so it could (did !). Control the heater on my Silvia without an SSR !

[nikko.the.scorpio]

Be aware that some of those PIDs are 12 volt DC input, which means you would need a suitable power supply to use them. That is an unnecessary complication.
Also many of them are single channel only, which is fine unless you want separate control of steam temp as well as brew water.
Search the 'bay for a XMT 7100 PID.
They are the smaller 1/32 DIN mini format, 240 v input, with SSR control output ( 8 volts) as well as a 240 volt relay and are usually about $25 post free. No soldering needed !
infact the internal 240 volt relay on mine was rated for 7amps, so it could (did !). Control the heater on my Silvia without an SSR !

Blend52, wow now thats a great sounding suggestion!

Love the smaller footprint - just makes sense and would allow multiple options of where to place - so thats great. I hadn't even thought about the 12V DC input needed on those other PIDs, which although I've loads of old power adapters I could use does seem like you're said to be an additional layer of complication.

However the real kicker is if I'm understanding what you're saying correctly there's no need for the additional 25A SSR! Well that certainly simplifies matters a LOT doesn't it. Gee thats a really solid suggestion and I don't think you could beat that one for overall fit for purpose suitability. Plus surely the install is that much simpler as well.

Great suggestion, I'll see if I can find a few. :-)

[saeco_user]

You definitely want one with SSR output so you don't have to open and remove any components. They are cheap and easily available.

This one is on cheapbay ($20): Digital PID Temperature Controller +max.40A SSR +K Thermocouple 0-400℃

Looks like it has almost the exact same specs and components as the MYPIN I was using.
I think it has the SSR output (sticker on side says so), but not sure if it has the separate relay output as well.
I don't know how useful regulating the steam temp is anyway, it's not as if you leave the boiler at this temp for any length of time.
Replacing the 125C thermal switch with a 140C switch made a decent improvement for me.

I'm not sure if this is the "best" option, but certainly I would suggest it is "good enough" for the job.
Save your money and buy a decent Crimp Tool.

Taan

ps the model suggested by blend52 may look nicer if you intend mounting internally to the Silvia.

[nikko.the.scorpio]

Thanks again for the replies - the real kicker for the XMT7100 suggested by Blend52 is that he seems to be implying that it doesn't need to be used with an external SSR. Now I'm a bit of a novice with electrical parlance however when I just searched for the XMT7100's manual, using this: http://www.berriman.co.uk/wp-content...11/xmt7100.pdf
It seemed to state that atleast officially it's relay contact was only 3A - which would not seem suitable - Every other retailer selling them seems to officially say the same 3A output only. Please don't get me wrong I am not saying Blend52 is incorrect or saying anything unture as I'm sure the relay on his XMT7100 is 7A - BUT perhaps thats the exception to the rule and as such not something you could order and count on receiving. :-/

I managed to find that GearBest stocks them and has them on special for around $USD17 a pop but seems maybe Blend52 got lucky with his - in which case it's much the same as the others though good to know about the input voltage and also size options. :-/

So might be back to the drawing board with the other candidates (though I suspect there's not a huge amount between them).

[saeco_user]

from memory, I think a few people had PIDs with specs listed as 3A output, but when they opened them, found the internal relay was actually rated for a much higher current.
I guess it would be pot luck when purchasing one.
You can probably purchase one with a higher specified output current at greater cost.
I would like to know what it's like having the element switched through a relay rather than an SSR. When at steady state there is quite a lot of switching happening to maintain the temperature at its set point.
The light on the front flickers regularly which may be even more annoying if accompanied by the continuous "clicking" of a relay.

I reckon the smaller format PID is still worth considering for use with an SSR.

[nicovington]

Thanks again for the replies - the real kicker for the XMT7100 suggested by Blend52 is that he seems to be implying that it doesn't need to be used with an external SSR. Now I'm a bit of a novice with electrical parlance however when I just searched for the XMT7100's manual, using this: http://www.berriman.co.uk/wp-content...11/xmt7100.pdf
It seemed to state that atleast officially it's relay contact was only 3A - which would not seem suitable - Every other retailer selling them seems to officially say the same 3A output only. Please don't get me wrong I am not saying Blend52 is incorrect or saying anything unture as I'm sure the relay on his XMT7100 is 7A - BUT perhaps thats the exception to the rule and as such not something you could order and count on receiving. :-/

I managed to find that GearBest stocks them and has them on special for around $USD17 a pop but seems maybe Blend52 got lucky with his - in which case it's much the same as the others though good to know about the input voltage and also size options. :-/

So might be back to the drawing board with the other candidates (though I suspect there's not a huge amount between them).

In the manual you linked, take a look at "7. Device Application Example"

It shows terminal 9/10 driving the SSR (this is a voltage output), and 4/5 being used for an alarm contact (this is a voltage free contact). The alarm contact is likely the 3A figure that you are seeing.

Specs from manual:
SSR activated voltage: open circuit: 10V; short circuit: 40mA.
Relay Contact: 220VAC, 3A. <--- ALARM in the diagram

Also briefly glancing at the manual, it looks like you can use either the SSR output or relay output from the PID control itself. You could actually use the alarm contact in conjunction with the SSR (if it didn't already have a suitable output), however the main problem here is that you need an external DC voltage to drive the SSR (and using the relay contact to apply voltage to the SSR).


@ saeco_user. There is not much difference switching between relay vs. SSR in terms of end user. As you notice, the relay clicks on and off. SSR's do have an internal resistance, which would be more problematic at high currents and lower voltages due to the voltage drop it would introduce. Should not be a problem here.

[blend52]

I will just throw this in for the sake of information.
..another unit I have used effectively in place of a traditional thermostat or a PID, is a Digital temp controller ( electronic thermostat )
they are very similar to a PID , but without the sophisticated control algorithms, for super fine temp control.
Same size and functions as a PID,..LED display of temp, adjustable temp, control within 1 deg, etc.
BUT.. They are cheap , $10 is normal on the 'bay, come with a thermocouple, and have an internal relay rated for 220/240v , 30 amps ! ( thirty ), so definitely no need for a SSR.
Just basicly a simple, cheap way of replacing the traditional thermostat and reducing the dead band from 15-20 deg down to 1-2 deg.

[FJP84]

I will just throw this in for the sake of information.
..another unit I have used effectively in place of a traditional thermostat or a PID, is a Digital temp controller ( electronic thermostat )
they are very similar to a PID , but without the sophisticated control algorithms, for super fine temp control.
Same size and functions as a PID,..LED display of temp, adjustable temp, control within 1 deg, etc.
BUT.. They are cheap , $10 is normal on the 'bay, come with a thermocouple, and have an internal relay rated for 220/240v , 30 amps ! ( thirty ), so definitely no need for a SSR.
Just basicly a simple, cheap way of replacing the traditional thermostat and reducing the dead band from 15-20 deg down to 1-2 deg.

Hi, is it possible to send information how to install this on a Rancilio Silvia or alike?