Author Topic: DIY SCPI programmable dual channel bench PSU 0-50V/3A (now EEZ H24005)  (Read 344979 times)

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Offline prasimix

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Any chance of an update? I can't wait to get mine!

Please follow this thread. I'm going to place a new update on the campaign pages when assembled PCB modules arrived.
 
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Offline Helix70

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Thanks, will do,
 

Offline void_error

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Re: DIY SCPI programmable dual channel bench PSU 0-50V/3A (now EEZ H24005)
« Reply #702 on: June 13, 2017, 12:19:39 pm »
I was looking at the post-regulator schematic on GitHub and noticed R63 is 0R16, shouldn't it be 0R18 to get 10*R65 (10*0R02) on the 500mA range when they're in series?
Trust me, I'm NOT an engineer.
 

Offline prasimix

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Re: DIY SCPI programmable dual channel bench PSU 0-50V/3A (now EEZ H24005)
« Reply #703 on: June 13, 2017, 02:31:00 pm »
You're right, but it seems that something lower is needed because with 0R18 I didn't manage to get full scale (500 mA) for calibrated channel. If I remember correctly max. value for full range was about 0R176 so I picked the next lower value that is easy to obtain.

Offline Helix70

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Re: DIY SCPI programmable dual channel bench PSU 0-50V/3A (now EEZ H24005)
« Reply #704 on: June 19, 2017, 11:40:37 pm »
I noticed on your blog post that you are having trouble sourcing the ZL305-08.

A substitute might be the Samtec CES-108-01-G-S, available at Digi-Key.

https://www.digikey.com/product-detail/en/samtec-inc/CES-108-01-G-S/SAM10955-ND/6692680
 
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Offline prasimix

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Re: DIY SCPI programmable dual channel bench PSU 0-50V/3A (now EEZ H24005)
« Reply #705 on: June 20, 2017, 06:31:38 am »
Thanks for that! It looks good. I had trouble finding part with height of 5 mm, most of them are about 7-8 mm. Anyway, what was said in latest update is still valid, ZL305-08 was already purchased and will be included with each bare PCB's set.

Offline Cthulhoid

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Re: DIY SCPI programmable dual channel bench PSU 0-50V/3A (now EEZ H24005)
« Reply #706 on: July 07, 2017, 02:14:20 am »
I'm guessing now that your campaign has ended there is no way to order one until the next batch?

You're right (if next batch happen).

Reading the other thread I understand why that's an "if". Of course, my current power supply decided to die this week to reinforce the message that I should have pre-ordered when I had the chance.  :(
 

Offline prasimix

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Firmware v1.01
« Reply #707 on: July 19, 2017, 02:57:02 pm »
A new firmware minor release (v1.01) is now available on the GitHub that fix a problem with channel's calibration for older Power boards (i.e. r5B9). It has also include few other small fixes and improvements including possibility to choose which USB port will be used for serial communication (firmware upgrade and SCPI control). The so-called native USB is now set as default one.

Offline prasimix

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Small hack for better current sensing?
« Reply #708 on: August 12, 2017, 09:57:19 am »
I was played recently with few ideas how to reduce offset caused by current sense resistor heating as discussed few posts ago and what was reported as issue #40. I tried to cut current sense resistor R65 value to half (from 0R020 to 0R010). That also require IC7 gain to double (R60, R70 from 1K91 to 3K9). Of course the low range resistor R63 is also changed from 0R160 to 0R082.
But I also glued a small heatsink on R65 as shown on the following pictures:





It seems that offset is now more then three times better (lower). Mounting of heatsink is not optimal, since the R65 is tiny (2512) in comparison with heatsink surface, but thermal glue did the job (after 24 hours of drying). We'll see if such mounting will survive for extended period of time. Used heatsink is ICKSMDK8SA.

 
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Offline Strada916

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Re: DIY SCPI programmable dual channel bench PSU 0-50V/3A (now EEZ H24005)
« Reply #709 on: August 12, 2017, 11:03:51 am »
I got an email this morning saying my PSU is on its way. Yay. Sorry for hijacking.

Sent from my SM-A520K using Tapatalk

The Bone, the Off-White, the Ivory or the Beige?
 

Offline John_K

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Re: DIY SCPI programmable dual channel bench PSU 0-50V/3A (now EEZ H24005)
« Reply #710 on: August 18, 2017, 01:48:46 am »
I just received my unit and have it mostly assembled.

The fit is very good except for the front panel: the PCB appears to be forced away from the front panel on the right side (where the two F1 boards plugin) - this causes the upper case to not align with the screw holes on the two F1 boards and the mounting screw for the front right foot pushes up against the front panel PCB.
 

Offline soeren72

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Re: DIY SCPI programmable dual channel bench PSU 0-50V/3A (now EEZ H24005)
« Reply #711 on: August 18, 2017, 06:28:52 am »
Also got mine, noticed the missing screws, but had them myself.
small angle on the connection between front board and power boards, connector i gaping 1mm, so not big problem
Screws for the feet was hell to get in, because of paint.
Calibration went fine, everything just works. and I enjoy using it  :)

Big thanks to prasimix
 
 
 

Offline prasimix

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Re: DIY SCPI programmable dual channel bench PSU 0-50V/3A (now EEZ H24005)
« Reply #712 on: August 18, 2017, 06:29:40 am »
I just received my unit and have it mostly assembled.

The fit is very good except for the front panel: the PCB appears to be forced away from the front panel on the right side (where the two F1 boards plugin) - this causes the upper case to not align with the screw holes on the two F1 boards and the mounting screw for the front right foot pushes up against the front panel PCB.

I'm not really sure that I understand your problem. Yes, it's true that right side of the PCB is slightly higher when mounted but that shouldn't make any problem to plug in both Power modules in place.

Offline texaspyro

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Re: DIY SCPI programmable dual channel bench PSU 0-50V/3A (now EEZ H24005)
« Reply #713 on: August 18, 2017, 05:40:33 pm »
My unit powers up and did the touchscreen cal.   But it fails self test with ADC and IOEXP failures on both CH1 and CH2.  Any ideas?
 

Offline prasimix

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Re: DIY SCPI programmable dual channel bench PSU 0-50V/3A (now EEZ H24005)
« Reply #714 on: August 18, 2017, 09:07:58 pm »
My unit powers up and did the touchscreen cal.   But it fails self test with ADC and IOEXP failures on both CH1 and CH2.  Any ideas?

Oops, that doesn't sound good. Please check if you have +48V on power board inputs first.

Offline texaspyro

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Re: DIY SCPI programmable dual channel bench PSU 0-50V/3A (now EEZ H24005)
« Reply #715 on: August 18, 2017, 10:45:47 pm »
My unit powers up and did the touchscreen cal.   But it fails self test with ADC and IOEXP failures on both CH1 and CH2.  Any ideas?

Oops, that doesn't sound good. Please check if you have +48V on power board inputs first.

I found the problem...  red and black wires swapped in one of the 48V Molex connectors...  cable making monkeys need to be spanked...

I fixed that and channel B started passing.    Chan A still had I/O expander and DAC errors.  I tried swapping power boards between the channels and still had problems.   I then started to do a more methodical swap / record results and it started passing self tests...  I haven't had a chance to put it through it's paces.


 

Offline prasimix

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Re: DIY SCPI programmable dual channel bench PSU 0-50V/3A (now EEZ H24005)
« Reply #716 on: August 19, 2017, 06:29:27 am »
My unit powers up and did the touchscreen cal.   But it fails self test with ADC and IOEXP failures on both CH1 and CH2.  Any ideas?

Oops, that doesn't sound good. Please check if you have +48V on power board inputs first.

I found the problem...  red and black wires swapped in one of the 48V Molex connectors...  cable making monkeys need to be spanked...

I fixed that and channel B started passing.    Chan A still had I/O expander and DAC errors.  I tried swapping power boards between the channels and still had problems.   I then started to do a more methodical swap / record results and it started passing self tests...  I haven't had a chance to put it through it's paces.

Ok, so issue with one Power board is resolved. If second one still have a problem, then you can disconnect it from the Arduino shield (on the front panel) to check easier under power bias voltages on ferrite beads FB1 (+5V), FB2 (+5V) and FB3 (-5V).


Offline texaspyro

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Re: DIY SCPI programmable dual channel bench PSU 0-50V/3A (now EEZ H24005)
« Reply #717 on: August 19, 2017, 12:11:39 pm »

Ok, so issue with one Power board is resolved. If second one still have a problem, then you can disconnect it from the Arduino shield (on the front panel) to check easier under power bias voltages on ferrite beads FB1 (+5V), FB2 (+5V) and FB3 (-5V).


Everything seems to be working now.   The swapped wires in one of the power cables fixed the problem where both channels were failing.   After fixing the cable,  the issue where only one channel was failing seemed to be related to a bad connection somewhere (power cable or front panel).  I'm thinking power cable.  Anyway, it's working now.

It might be useful to be able to go into some diagnostic mode (instead of just hanging) if the self tests fail.  Not sure what that mode can / would do though.
 

Offline prasimix

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Re: DIY SCPI programmable dual channel bench PSU 0-50V/3A (now EEZ H24005)
« Reply #718 on: August 19, 2017, 12:41:13 pm »
It might be useful to be able to go into some diagnostic mode (instead of just hanging) if the self tests fail.  Not sure what that mode can / would do though.

 :) Any additional diagnostic would require functional communication with existing peripherals on the Power boards (i.e. I/O expander, ADC and DAC) or more devices in parallel for probing and monitoring. But, if e.g. bias voltages are wrong or not available, or physical connection is compromised then we have limited possibility to acquire additional information that could be valuable for diagnostic.
Also as you can see, if just one channel didn't pass self-test another one will be available for use.

Still, if someone have any idea what to do on top of what we have now please open a new issue in Github.

Offline garnix

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Re: DIY SCPI programmable dual channel bench PSU 0-50V/3A (now EEZ H24005)
« Reply #719 on: August 19, 2017, 01:54:10 pm »
Or is there a description which colorored cable goes into which slot in the connector? So we can quickly check if the cables are correcly wired?
 

Offline prasimix

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Re: DIY SCPI programmable dual channel bench PSU 0-50V/3A (now EEZ H24005)
« Reply #720 on: August 19, 2017, 01:57:23 pm »
Or is there a description which colorored cable goes into which slot in the connector? So we can quickly check if the cables are correcly wired?

Yes, such information are available under Wire harness section on the web (PDF version for download is also available).
« Last Edit: August 20, 2017, 12:37:52 pm by prasimix »
 
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Offline texaspyro

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Re: DIY SCPI programmable dual channel bench PSU 0-50V/3A (now EEZ H24005)
« Reply #721 on: August 19, 2017, 02:14:10 pm »
Also maybe, if one channel passes and the other fails,  allow it to work in single channel mode.  That way the unit is semi-usable if a power card craps out.  I suspect that a very large percentage  of use of the supply will be single channel.
 

Offline prasimix

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Re: DIY SCPI programmable dual channel bench PSU 0-50V/3A (now EEZ H24005)
« Reply #722 on: August 19, 2017, 02:18:19 pm »
Also maybe, if one channel passes and the other fails,  allow it to work in single channel mode.  That way the unit is semi-usable if a power card craps out.  I suspect that a very large percentage  of use of the supply will be single channel.

That we already have. All what you need is to click on "Home" icon on self-test error report page.
You can do that even if both channel didn't pass self-test. Obviously there is no use of it except that it allow access to system settings page.

Offline Dwaine

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Re: DIY SCPI programmable dual channel bench PSU 0-50V/3A (now EEZ H24005)
« Reply #723 on: August 20, 2017, 06:19:43 am »
Or is there a description which colorored cable goes into which slot in the connector? So we can quickly check if the cables are correcly wired?

Confirming my cables were fine out of the box. 
 

Offline Rerouter

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Re: DIY SCPI programmable dual channel bench PSU 0-50V/3A (now EEZ H24005)
« Reply #724 on: August 25, 2017, 01:19:13 pm »
Just built mine, seems to be 6 missing black screws for mine, not 2, (one visit to rs components later) only the 2, little bag of 4 was under a cardboard fold

So far i haven't run the calibration, but no smoke has been released as of yet. the UI, and USB both are working fine,
« Last Edit: August 25, 2017, 08:16:39 pm by Rerouter »
 


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