Author Topic: EEZ Bench Box 3 (BB3)  (Read 52764 times)

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Online Kleinstein

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Re: EEZ Bench Box 3 (BB3)
« Reply #400 on: October 18, 2020, 03:15:54 pm »
For the reaction of the constant current limiting there are 2 components: one is the output capacitor. 33 µF are more on the low side for a lab supply if charged to some 30 V and with low ESR it may be enough to stress a fuse. There is not very much one can do about this - the regulator needs some capacitance and the lower the capacitance the higher the chance to get overshoot in the CV to CC transition. The only thing that may get a slight improvement is from some series resistance to the large part of the capacitance - so not a low ESR cap, but more like a higher ESR one. The parallel ceramic cap is good for the highest frequencies and provides the low ESR there.

The other contribution to the current surge is from the time it takes for the regulator to react. Here it could be a slight problem that the CV loop looks quite fast compared to the CC loop. So the CV part may increase the current too much before the CC part starts reacting. Initially the OP (IC10A) from the CC loop is near positive saturation and it takes some time to discharge C55. A possible known counter measure would be to have the left side of C55 connected to the other side of the diode D13. This way the capacitor would not start from so high and the CC mode can react faster (possibly unpleasantly fast for some uses).
I don't know the size of the 2 nd contribution - it could be comparable to the output cap.
 
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Offline prasimix

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Re: EEZ Bench Box 3 (BB3)
« Reply #401 on: October 18, 2020, 03:21:28 pm »
33uF I guess would do it for sure....

Yes, it is out of CC control loop control.

Offline prasimix

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Re: EEZ Bench Box 3 (BB3)
« Reply #402 on: October 18, 2020, 03:31:33 pm »
A possible known counter measure would be to have the left side of C55 connected to the other side of the diode D13. This way the capacitor would not start from so high and the CC mode can react faster

Hm, this is an interesting detail. I will try to test it (first to come up with some satisfactory solution on the other front :)).

Offline elekorsi

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Re: EEZ Bench Box 3 (BB3)
« Reply #403 on: October 18, 2020, 03:36:39 pm »
I decided to check the response for CC and here are the results. First screenshot is with 100ohm resistor across the output, the second one is with 1ohm and the third one is a 1us detail of current on 1ohm. Yellow is voltage, purple is current.
When i checked the datasheet of the fuse it is clear that the fuse did exactly as expected... ;D
 

Offline prasimix

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Re: EEZ Bench Box 3 (BB3)
« Reply #404 on: October 18, 2020, 03:40:39 pm »
You are using OE ON/OFF control or just touch wire as @IanJ explained?

Offline elekorsi

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Re: EEZ Bench Box 3 (BB3)
« Reply #405 on: October 18, 2020, 03:54:40 pm »
That was a wire touch, as i wanted to see why my fuse had blown  8)

ON/OFF method is on the bellow picture, 20mA set, 1ohm resistor across the output
 

Offline prasimix

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Re: EEZ Bench Box 3 (BB3)
« Reply #406 on: October 18, 2020, 03:55:45 pm »
OK, so everything is under control when it is under control  :-+
 
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Offline prasimix

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Re: EEZ Bench Box 3 (BB3)
« Reply #407 on: October 18, 2020, 03:59:24 pm »
For repetitive stress testing one can use list programming. For example, I made this simple step from 0 to 50 mA, with voltage set to max, and repeat that test 1000 times with 200 mA fuse directly connected to the power output:



... and you can observe that in YT view (refresh rate is set to 5 ms, upper current limit is set to 60 mA for better current view):



 
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Offline gojimmypi

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Re: EEZ Bench Box 3 (BB3)
« Reply #408 on: October 18, 2020, 06:20:19 pm »
Heads up on a case grounding issue I found on my BB3. Seems the nice paint does too good of a job being an insulator! (details, details).

I posted a blog:https://gojimmypi.blogspot.com/2020/10/envox-eez-bench-box-3-ground.html on how I scraped a bit of the paint off of the case at the standoffs and added a wired connection to improve ground safety.
 
 
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Offline IanJ

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Re: EEZ Bench Box 3 (BB3)
« Reply #409 on: October 19, 2020, 09:28:17 am »
Hi all,

Possible small issue on Current reading on display (actual Current).

When a load is disconnected, sometimes the Current display will drop down to 0A, sometimes 0mA.
You can see it jump between 0 Amps and 0 mA and seems a little random on where it actually lands.

It looks like it may be down to a calibration artefact, i.e if when the load is disconnected and the zero Current to be displayed is a little off, say -0.5mA then it will display mA.......and maybe if it is NOT off then it can land on 0A and stay there. Albeit not 100% sure about this though because I have seen 0mA exactly being displayed (but could be rounded).

Confused?.....I can easily create a video to demonstrate if req'd.

Ian.
Ian Johnston
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Manufacturer of the PDVS2 & PDVS2mini
 
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Offline prasimix

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Re: EEZ Bench Box 3 (BB3)
« Reply #410 on: October 19, 2020, 09:33:15 am »
Thanks Ian, message taken :). I'll add that in existing #73.

Offline IanJ

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Re: EEZ Bench Box 3 (BB3)
« Reply #411 on: October 19, 2020, 02:57:09 pm »
Hi all,

Really enjoying my BB3, in the coming weeks it's going to be used extensively whilst I test a whole production run of boards.............Anyways, just another minor level issue:-

I have confirmation turned ON and use DARK mode.
After V or I entry is made and with the default "10" for Lightness the flashing yellow/white is ok, but not great. Turn the Lightness up any further and it's barely seeable. Turn it down to say "5" and it's better.
I think maybe the colours could be tweaked to make the flashing-await-confirmation much more obvious.
Also, yellow is really assigned to #1, whilst green is for #2, so wonder if yellow flashing for all confirmations on all channels is the best (just being picky here!).
PS. I have kinda settled on Brightness = 20, Lightness = 5.

Also, could you have Encoder Step (via User SW) setting retained on power up.

Ian.
« Last Edit: October 19, 2020, 03:06:23 pm by IanJ »
Ian Johnston
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Manufacturer of the PDVS2 & PDVS2mini
 

Offline prasimix

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Re: EEZ Bench Box 3 (BB3)
« Reply #412 on: October 19, 2020, 03:06:36 pm »
Hi all,

Really enjoying my BB3, in the coming weeks it's going to be used extensively whilst I test a whole production run of boards.............Anyways, just another minor level issue:-

I have confirmation turned ON and use DARK mode.
After V or I entry is made and with the default "10" for Lightness the flashing yellow/white is ok, but not great. Turn the Lightness up any further and it's barely seeable. Turn it down to say "5" and it's better.

I think maybe the colours could be tweaked to make the flashing-await-confirmation much more obvious.
Also, yellow is really assigned to #1, whilst green is for #2, so wonder if yellow flashing for all confirmations on all channels is the best (just being picky here!).

PS. I have kinda settled on Brightness = 20, Lightness = 5.

Ian.

Thanks, reported as #76.

Offline prasimix

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Re: EEZ Bench Box 3 (BB3)
« Reply #413 on: October 19, 2020, 03:18:45 pm »
Also, could you have Encoder Step (via User SW) setting retained on power up.

Reported as #77.

Offline IanJ

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Re: EEZ Bench Box 3 (BB3)
« Reply #414 on: October 19, 2020, 04:07:19 pm »
prasimix,

With Keysight IO libraries I can query/response the BB3.....but from my own VB app I can make a valid connection but can't query the BB3 at all. I get an error responce.

I have written my own VB app but it uses an extensive GPIB library from PavelW. The IO library returns "MAV bit not set" when I try to query the BB3.
The developer of that library I remember he came across somebody else with the same issue try to connect to a DMM and offered the following repsonce at the time.

Quote
If the message is "MAV bit not set" then it is clear: your meter is not quite compliant with the 488.2 specification on the meaning of status byte bits. I explain. Polling the status byte is used here to check if the device is ready to send response, according to 488.2 this information is coded in the "Message Available" bit of the status byte, the bit 5 (so the default mask used is 16).
Keysight interactive IO works because it does not use any information from the status byte: when you hit "read" it calls the raw low-level read function which waits until it gets response.  But then once a "read" is issued the whole gpib bus will remain blocked until your meter is done with the measurement - very annoying if you have more than one devices connected, especially with high NPLC where it can take seconds to respond.  This software uses periodic polls to check if the data is available, before calling "read", in this way the bus remains available and the program is able to query two (or more) devices simultaneously.  This is the default configuration but it can be easily disabled on per-device basis (you may do it yourself or ask Ian to add checkboxes controlling the "enablepoll" flag for each device).  For a more elaborate version, the MAV masks can also be set individually for each device.

The above just my quick initial ideas as to the problem.........
I can work around it per what Pavel suggests and implement a checkbox in my app to enablepoll.........but just wondered initially your thoughts.

Ian.

Thanks for this. Martin will investigate and we'll let you know what he found. If you have a chance to get some VB sample, it could speed things up for me.

UPDATE:
I have spoken to the GPIB library developer and it turns out it appears that the BB3 implementation is raw socket connection only.

The GPIB library compatibility I have is with the more usual Visa "INSTR" devices using the standard VXI11 or HiSlip protocol.
Actually, the full list of options:
- Visa
- GPIB: ADLink
- GPIB488.dll
- Com Port

So, at the moment I am not able to control the BB3 from my own GPIB app.......unless I can look into modding the library code myself to add VB.NET TCP/IP (getting towards my limits on this and might push my knowledge of VB & GPIB!).

Ian.
Ian Johnston
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Manufacturer of the PDVS2 & PDVS2mini
 

Offline prasimix

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Re: EEZ Bench Box 3 (BB3)
« Reply #415 on: October 20, 2020, 07:22:16 am »
I understand, but what's about "Com Port" that is also mentioned? Does it means USBTMC or virtual com?
Adding VXI-11, HiSlip (or LXI) we'll be considerable effort for us in this moment, maybe not if some nice open source lib are available. Perhaps we could work with GPIB library developer that you mentioned and see what he is using and what is a possiblity to work with "raw" (telnet) connection.

Offline IanJ

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Re: EEZ Bench Box 3 (BB3)
« Reply #416 on: October 20, 2020, 08:08:14 am »
I understand, but what's about "Com Port" that is also mentioned? Does it means USBTMC or virtual com?
Adding VXI-11, HiSlip (or LXI) we'll be considerable effort for us in this moment, maybe not if some nice open source lib are available. Perhaps we could work with GPIB library developer that you mentioned and see what he is using and what is a possiblity to work with "raw" (telnet) connection.

For my purposes and having GPIB working on teh BB3 with my App it's a "nice to have"......so wouldn't want you to go out your way to spend a lot of time to implement INSTR etc.
The GPIB library developer has already told me he's got no time to implement TCP/IP socket at the moment, although you could always contact him and ask questions.....he's a GREAT guy.
https://www.codeproject.com/Articles/1166996/Multithreaded-communication-for-GPIB-Visa-Serial-i

Com port = Although Visa can be used to access serial ports it was simple to write an implementation using the standard SerialPort class provided in .NET.....thus does not require any Visa resources.
"COM1:9600,N,8,1,CRLF"
I have never used the library inthis way so don't know much more than this.

Ian.


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Manufacturer of the PDVS2 & PDVS2mini
 

Offline IanJ

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Re: EEZ Bench Box 3 (BB3)
« Reply #417 on: October 20, 2020, 08:42:02 pm »
Hi,

When logging the brown background behing the Current display isn't full width.......or is this a dynamic display? (haven't fully tested the functionality yet).

Ian.

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Manufacturer of the PDVS2 & PDVS2mini
 

Offline prasimix

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Re: EEZ Bench Box 3 (BB3)
« Reply #418 on: October 20, 2020, 09:22:51 pm »
Thanks Ian, it a bug. Reported as #80.

Offline IanJ

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Re: EEZ Bench Box 3 (BB3)
« Reply #419 on: October 20, 2020, 10:22:18 pm »
Thanks Ian, it a bug. Reported as #80.

Also, I think the brown background behind the voltage display is 1 pixel to the right.

Ian.
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Manufacturer of the PDVS2 & PDVS2mini
 

Offline jan28

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Re: EEZ Bench Box 3 (BB3)
« Reply #420 on: October 21, 2020, 03:26:18 pm »
Hello,

If the user switch is set to change the encoder step this works in most places where the encoder works but not in the 'edit list' screen (running firmware v1.3.2). In this menu the encoder and pressing the encoder switch behave consistent with other screens.

[attach=1]

Jan

 

Offline elekorsi

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Re: EEZ Bench Box 3 (BB3)
« Reply #421 on: October 21, 2020, 07:01:01 pm »
Just for info, we have a very thorough beta tester on the case. If there is a bug in the UI, he will find it, believe me  :-DD
 
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Offline AlanS

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Re: EEZ Bench Box 3 (BB3)
« Reply #422 on: October 21, 2020, 10:03:51 pm »
For Australians:
All shipping documents said that the unit would arrive tonight; I picked it up 2 days ago. Amazingly it got to Melbourne in about 3 days and then sat in limbo for a few more. Fairly typical I suppose.

Unit arrived with packaging in good condition and as expected exhibits Envox's high standards. I'm looking forward to the additional modules and perhaps an extra frame.

A word of warning though. My CPU board had its USB connector floating around inside the bag. It later jammed itself under IC4. So please, don't just blindly plug the boards in and power up - check for any manufacturing issues. Denis and Martin don't need any more heartaches due to their previous dodgy supplier.

Alan
 
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Offline Andrew McNamara

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Re: EEZ Bench Box 3 (BB3)
« Reply #423 on: October 22, 2020, 12:07:42 am »
A word of warning though. My CPU board had its USB connector floating around inside the bag. It later jammed itself under IC4. So please, don't just blindly plug the boards in and power up - check for any manufacturing issues. Denis and Martin don't need any more heartaches due to their previous dodgy supplier.

I had the same problem - USB connector and "boot0" button floating around where they should not be. Parts and PCB were undamaged. Solder looks granular, making me think they did not receive enough heat during reflow. Everything else was perfect, though, and it went together smoothly.
 
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Offline AlanS

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Re: EEZ Bench Box 3 (BB3)
« Reply #424 on: October 30, 2020, 05:47:37 am »
Well I finally got around to building my BB3. What a lovely piece of gear and the basis for a data acquisition unit I need for module testing. Denis, I need the second frame.

I'm full of admiration for Andrew McNamara. He evidently had few issues retrofitting the USB connector. With my old eyes it was no fun at all. The language was colourful and would have been educational for grandkids were they allowed to visit in Danistan - read Victoria, Australia.

I now have one DCP405 module (A) working as expected - the other (B) not so much. Switching AC-DC pre-power supplies and positions in the backplane produces the same results. That is A works and B is different.

B has a maximum output voltage of about 200mV and goes out of CV mode at about this point. Hmmm. Time to look for the circus diagrams. :scared:
 
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