DIY SCPI programmable dual channel bench PSU 0-50V/3A (now EEZ H24005)

[prasimix]

AUX power supply will go to the space where PSU are at the moment.... Thanks!

Mind that AUX PS module has three connectors on its back. You can mount it on rear panel (or any other if you wish) with five 14 mm spacers.

[Strada916]

Suggested modules constellation is not possible with current Arduino shield at least not without adding extender 26-pin flat cables. Also if Power boards are far away from each other you'll need two instead of one cooling fan. That will also need additional fan speed controller.
Currently only what is possible is to rotate AC/DC power modules, increase enclosure depth and try to stay within width of Arduino shield that is 220 mm.

It looks that I should keep Arduino & two power boards together as they are now. I'll go for taller enclosure to accomodate the shield on tow of two AC/DC PSUs side by side (this will add around 4-5cm) under it. AUX power supply will go to the space where PSU are at the moment.... Thanks!

Why not have the AC/DC module in a outside enclosure? That way you only have the PSU boards in the enclosure.

Sent from my D6503 using Tapatalk

[prasimix]

I had a chance to test Passives EC12E20-24P24C-SW and Bourns PEC11R-4015F-S0024 encoders. With encoder algorithm that is recently changed and I can say that both of them works nice. The difference is that former has discrete steps (detents) that you can feel when you turning it, while later is like analog pot, operating very smoothly (and it's more expensive).
Don't know what people will prefer more.

[cs.dk]

Personally i like encoders with indents, steps or what ever the correct English term is

[Kean]

The correct English term is "detent" - https://en.wikipedia.org/wiki/Detent
And yes, encoders with detents are also my personal preference, but smooth ones do suit certain applications.

[prasimix]

Ok, the same Bourns series has models with detents, but I have to find one that is available in needed quantity. Another possibility is to find a model from some other company. I found that BI technologies also produce encoders, e.g. EN12-HS22AF20 that Farnell not stocked anymore but is available on Digikey and Mouser.

[prasimix]

Finally I managed to make a very short intro video of EEZ Studio. A more videos will follows and its source code will be uploaded on the GitHub in near future.

[jleg]

Finally I managed to make a very short intro video of EEZ Studio. A more videos will follows and its source code will be uploaded on the GitHub in near future.

that is really impressive - and looks promising.
I wonder if this tool would also be capable of creating GUI code for smaller units than DUE?
And is there also some possibility to handle multi-language setups?

[prasimix]

Thanks for your input. Arduino Due is not a target platform but any display that will be added and has Arduino library. Right now is possible to generate a code for both AVR and ARM MCUs via UTFT library. Problem with smaller MCUs it that they cannot be used with controllers that is covered with mentioned UTFT library (see yellow note here). Not because library is not good but because display controllers on such displays are primitive and required lots of code. That's the reason why we'd like to include displays with other controller like FT80x from FTDI/BridgeTek that you can be found on e.g. Riverdi displays. They have a great selection with both resistive and capacitive touchscreens and many screen sizes.

The EEZ Studio project file handles multiple languages and multiple display orientations (i.e. portrait and landscape).

Anyway idea is at the end to have something like Nextion but fully open source and not limited to just one display's manufacturer. Hopefully we'll make it happen in the near future.

[VEGETA]

it would be a great help if this great solution supports PIC microcontrollers.

[jleg]

Right now is possible to generate a code for both AVR and ARM MCUs via UTFT library. Problem with smaller MCUs it that they cannot be used with controllers that is covered with mentioned UTFT library (see yellow note

ok, UTFT - thanks, that answers my question; so it looks like a Mega could also be usable target - or a Teensy...

[garnix]

OK, I tried to make a preliminary bezel to fit the 3.2" display in the 3.5" hole: http://www.thingiverse.com/thing:2139511

It is just a first try - I took your new drawings from GitHub where you marked the dimensions for the 3.5" and 3.2" display: https://github.com/eez-open/psu-hw/blob/master/Mechanical/EEZ%20PSU%20H24005%20dual%20display%20hole.png

I don't know the exact distance the LCD display is recessed from the front-panel, so I just assumed some value.

There are multiple ways to do such a bezel:

• it could be flush with the front-panel - then it needs some support in the back to screw it to the metal case
• it could be raised from the front-panel - then it could "snap-in-place", this is the idea I used

According to your drawings, the two displays are not centered, so a possible bezel can not be symmetrical. I think it would be more aesthetically pleasing to make a symmetric bezel - because you could then do a nice inward-curved bezel.

I think if we stick with those non-centered displays, then two separate front-panels would look nicer and this bezel thing would probably not look that nice.

Some other things to think about: Someone would need to print those 300+ bezels 

[prasimix]

According to your drawings, the two displays are not centered, so a possible bezel can not be symmetrical. I think it would be more aesthetically pleasing to make a symmetric bezel - because you could then do a nice inward-curved bezel.

Thanks for that garnix. You're right I didn't manage to center them since 3.2" display position is defined with 40-pin connector that is plugged directly to the Arduino shield, while 3.5" display cannot be moved to much on the right since it's frame construction will overlap with 17 mm hole for encoder knob. The only solution to rectify that asymmetry is to move 40-pin 2 mm to the left (actually 2 mm to the right when viewing from the PCB top side).

[VEGETA]

can i ask how much shipping cost to jordan and usa for full unit? i mean device only price and shipping price?

450$ seems reasonable for it but other similar ones are the same without shipping which can cost something like 200$ to jordan!! is that how it people normally pay for such devices? i am really confused. also is it tracked or not.

thanks

[prasimix]

can i ask how much shipping cost to jordan and usa for full unit? i mean device only price and shipping price?

450$ seems reasonable for it but other similar ones are the same without shipping which can cost something like 200$ to jordan!! is that how it people normally pay for such devices? i am really confused. also is it tracked or not.

thanks

Direct shipment from Croatia to Jordan is $46. Tracking number is included.

[VEGETA]

what is the total weight? and what company do you use? Do you have Aramex?

[prasimix]

Mention price is for Croatian post service. Weight is 4 kg.

[VEGETA]

Jordanian post seems to have similar prices too or even lower. I tried Aramex and it is so expensive, I imagine DHL is the same too. However, is tracking good enough like these companies or not? also, delivery time?

[prasimix]

The new r5B12 PCBs arrived from ITEAD few days ago and I managed to assemble them to test if new added features are working as expected. All boards are now a little bit larger and I tried to keep the same mounting holes spacing as in previous builds.

AUX PS module





This module now has additional MCU controlled power relay with NO and NC pins exposed and reachable from the rear panel (X6 connector). Cooling fan power is now isolated, 5V buck is removed and dual output 5 W AC/DC module from Vigortronix is used instead.

Power board





It's possible now to work with two current range e.g. 0-500 mA and 0-5 A (on the picture that is down left corner section with Q13, Q14, R63, R65). Current shunt monitor op amp (IC7) is changed to LTC2050HV (see sheet #3). I also replaced bias power supply (see Sheet #2) where now TL781 and LTC3260 are used instead of buck regulator (LM5574).
I found two stupid mistakes on this PCB: the power input connector (X2) is rotated i.e. not the same as on the previous board, and choke L1 that is now smaller need different holes spacing.

Arduino shield





The most important changes here is encoder that can be now mounted directly on the PCB. Due to that TFT display is moved to the left. PE (Earth) terminal is moved below encoder.
I added 20-pin 0.5 mm FFC connector (X20) for future upgrade to Riverdi 3.5" touch screen display with FT800 (resistive) or FT801 (capacitive) controller. Since that display also has audio, a small audio amplifier is also added (TPA6205).
Playing with PCB layout I succeed to swap control lines for AC power (PWR_SSTART and PWR_DIRECT), but that is corrected and uploaded on the GitHub.

I need to test few more things and if everything is fine I can send to ITEAD final Gerbers and BOM to initiate PCB assembly of few sets first and after that to proceed with the rest that needed for crowdfunding campaign fulfillment.

[Strada916]

Love your work. When this thread started out i thought here we go another lab PSU. Well all i can say is great achievement and i look forward to my new PSU .

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[prasimix]

Yesterday I had a chance to see what's happen if so-called bias or feedback resistor is not present in oscillator circuit. W5500 Ethernet controller require 25 MHz clock, and I missed to add 1 Mohm in parallel with crystal. Without that resistor oscillator don't want to start on the r5B12 PCB revision (I didn't notice that on r3B4).

Anyway if anyone of you how has an issue with Ethernet please first check if oscillator is running (XO, pin 31 should have 25 MHz signal).

I added THT resistor as on picture below and that resistor became R176 (see Sheet #10) in latest build on the GitHub.

[prasimix]

I manage to activate a 3.5" Riverdi touch screen display. This is a cheaper resistive touch screen model with FT800 controller, and capacitive touch screen model with FT801 controller seems that is pin compatible.

Please note that display has to be rotated for 180 degrees since it's going to be mounted vertically not horizontally (as in a handheld device) for optimal viewing angle. On the picture below I just place it over Arduino shield but in practice it need its mounting rail or bezel (e.g. see garnix proposal in post #636) that has to be fixed on the front panel.



So now we have an upgrade path to more capable display (faster controller, truetype fonts, selection of resistive and capacitive touch screen, built in audio, etc.).

[mubes]

That looks great. Personally I would prefer to wait for this upgraded display (+matching bezel etc.) but that makes your logistics horrendously more difficult, I suspect....

DAVE

[prasimix]

Not just difficult but also impossible if we are talking about campaign fulfillment here. This display is many times more expensive and we'll need some time to add support for it. 

[VEGETA]

So the question is: what are the types of displays that are supported with this software of yours (EEZ studio)? I guess support for traditional PIC MCUs is not yet there so maybe just arduino ones?

I have designed a power supply circuit and it is working, next I will do the other stuff reaching down to display choice. Since I wanted to manufacture it I choose PIC MCU not arduino but driving TFT with a good design software is very hard for PIC or any other MCU as well as very pricey.

What will be more cost effective, your solution or something like Nixteon one?

thanks