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teardown, teardown!!
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What's the difference between the 3021 and 3021A?
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I was so excited when I saw this DC Load today and was about to order one, but then noticed that the battery test function doesn't display capacity in watt-hours on the device. I hope this gets added in a firmware update.
I don't understand why all the DC loads only test battery capacity in Ah. I sent Array and email requesting a firmware update so that it can display the battery capacity in Wh for my 3720A and about a week later I received a firmware file via email that supposedly adds this, however the firmware file is for the 3721A model and didn't work. I'm still hoping to receive the correct firmware file for my model, because it's a pain in the ass writing a script to do this calculation on a PC when it's so much more convenient if the device can do it. -
I sent Array and email requesting a firmware update so that it can display the battery capacity in Wh for my 3720A and about a week later I received a firmware file via email that supposedly adds this, however the firmware file is for the 3721A model and didn't work. I'm still hoping to receive the correct firmware file for my model, because it's a pain in the ass writing a script to do this calculation on a PC when it's so much more convenient if the device can do it.
Fun fact: I'm testing the battery capacity with a 3721A right now. Do you know if they plan on releasing the firmware version officially? Or maybe you could hook me up with yours? -
I sent Array and email requesting a firmware update so that it can display the battery capacity in Wh for my 3720A and about a week later I received a firmware file via email that supposedly adds this, however the firmware file is for the 3721A model and didn't work. I'm still hoping to receive the correct firmware file for my model, because it's a pain in the ass writing a script to do this calculation on a PC when it's so much more convenient if the device can do it.
Fun fact: I'm testing the battery capacity with a 3721A right now. Do you know if they plan on releasing the firmware version officially? Or maybe you could hook me up with yours?
I actually do not think they plan on releasing it officially, because this update is v1.53 and the latest one on the website is only v1.43. Even the updater utility I received is a year newer than the one on their website.
I'll gladly share the v1.57 update for the 3721A with you and you can let me know if it actually adds Wh readings to the battery test function. Send me your email address and I'll mail you the firmware and update utility right away.
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I sent Rigol an email requesting them to add Constant Power mode to the Battery Test function in order to measure battery capacity in Wh. I received an email back that they already have this feature in the pipeline and that it's expected to be ready at the end of the month. I'm really happy about that.
Are there any members on the forum with DL3000 series loads that would be willing to notify us on the forum when this feature gets added to the firmware? I would like to order a DL3021A if Rigol adds this feature to the load. -
I sent Rigol an email requesting them to add Constant Power mode to the Battery Test function in order to measure battery capacity in Wh. I received an email back that they already have this feature in the pipeline and that it's expected to be ready at the end of the month. I'm really happy about that.
That's great news! Anyone tested if the Rigol loads have the same problem as their power supplies that their PC control software doesn't work with region settings that use comma as the decimal point? -
cool
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Yesterday my new DL3021A arrived.
The first thing i noticed was that when i am just enabling the input it constantly show a current of around 2.2 mA even when not connected to any source. And in 4A-Mode where the spec of the current setting would allow a maximum of 2mA.
Ugh... A further look into the spec tells me that this value is within spec because - other than other loads - this device only has one current readback range. Other devices are using at least similar or even the same setting and readback-ranges. It's accuracy is specified with +-(0.05%+0.05%FS). FS is 40A, so up to 20 mA without any load would still be in spec.
WTF... why is there no 0 to 4A readback range with an accuracy similar to the input mode of the device? 
During testing i struggled in the constant resistance mode. I connected a 1.5V battery, switched to CR Mode, pressed 15, then "kOhm". The display showed "15 kOhm". After enabling, the device pulled around 70 mA from the Battery (and showed 15 Ohm in it's display).
The last time i got a new rigol device - function generator DG1062z - i had to exchange the device multiple times until i go a satisfying one. The first one had a hardware-failure, the second one was out of spec in frequency accuracy, the third one was acceptable (but there still was an software error when using the external 10Mhz-source after powering off the device).
I am really not shure if i will keep this rigol load. Maybe Maynuo would be more satisfying?
What are the disadvantages of Maynuo?
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I am really not shure if i will keep this rigol load. Maybe Maynuo would be more satisfying?
What are the disadvantages of Maynuo?
I haven't found any so far... It doesn't have fancy graphic screen, so for graphical approach you use software on a PC (which is pretty good). In a battery mode there is no W/hour measurements only A/hour... Everything else looks just perfect so far... -
Although the Maynuo 97/98-series loads are programmable they're not LXI and/or SCPI, it's got no USB or Ethernet port, instead it uses MODBUS RTU over a un-isolated (ie the common for the TX/RX-signals is connected to negative terminal of the input) TTL-level UART-connection for which you generally would want to use their M-131 or M-133 isolated level translator cable - or a similar DIY type of thing.
If you're into automation and have other instruments speaking SCPI then having to mess around with MODBUS as well may be a disadvantage.
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ah... from what i can actually see the main disadvantage for me is that the Mayunos have no selectable slew-rate setting. Automation wouldn't be a big issue as long as there is a good pc-software to get graphs for documentation purposes.
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MODBUS is mature industry standard.. Very robust and versatile, and not that hard to learn and use.. Isolated cable is no problem, to make or buy. You can also connect to RS485 and run 400 meters cable run ... Also, with RS485, it's a bus, so you can connect multiple devices on a same cable, each with it's address... Maynuo supports that mode...
All registers and commands are explained in user manual.. And from a program you speak to it as a normal serial port, so no special libraries.. You need to calculate checksums on packets, but that is not hard to write (once) or there is tons of ready made libs in C, python and whatnot ..
If you are into automation, you need to know MODBUS anyways....
Don't look at it as a hardship but as an opportunity to learn.. -
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MODBUS is mature industry standard.. Very robust and versatile, and not that hard to learn and use..
Oh, absolutely, it's a mature industry standard, I wasn't saying or implying it wasn't.QuoteIf you are into automation, you need to know MODBUS anyways....
If you're into industrial automation yes, most likely you should know MODBUS. But I'm not equally sure MODBUS is that common in T&M automation - scopes, power supplies, spectrum analyzers, that kind of thing. And if the rest of your test setup uses LXI then having to deal with MODBUS over a serial connection might be considered a disadvantage over an instrument that does support LXI, that's all I'm saying.QuoteDon't look at it as a hardship but as an opportunity to learn..
It all depends on who's buying and for what. It might be you have been assigned a task to complete, you might want (or might have to) choose the path of least resistance, because the task has to be finished in a timely manner. Then having to deal with (and possibly learn from scratch) another protocol might, again, be a disadvantage. If you're not even DOING any automation then obviously it doesn't matter much - if at all.
I have a Maynuo e-load and it's the only programmable instrument on my shelf that uses MODBUS, my other four programmable instruments all uses SCPI, to me that's a disadvantage even though I do know MODBUS fairly well, having written uC code for MODBUS RTU. -
ah... from what i can actually see the main disadvantage for me is that the Mayunos have no selectable slew-rate setting. Automation wouldn't be a big issue as long as there is a good pc-software to get graphs for documentation purposes.
Of course they have, who told you that? You can set rise and fall time separately, from 0.1/usec to 30 sec in transient mode... It is annoying that you can't do it interactively though...
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Of course they have, who told you that? You can set rise and fall time separately, from 0.1/usec to 30 sec in transient mode... It is annoying that you can't do it interactively though...
Ah... this is what i saw in the manual (it was not mentioned anywhere). But now as you were speaking about it i did search again. I was only looking for the terms of slew rate. When looking for rise time, i can find the references. So another checkmark on the positive side of maynuo.
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The last time i got a new rigol device - function generator DG1062z - i had to exchange the device multiple times until i go a satisfying one. The first one had a hardware-failure, the second one was out of spec in frequency accuracy, the third one was acceptable (but there still was an software error when using the external 10Mhz-source after powering off the device).
Unfortunately this seems to be par for the course when Rigol first brings a new device to market.QuoteI am really not shure if i will keep this rigol load.
I would definitely recommend testing it as much as you can, and if you aren't comfortable that you can live with the bugs you (and others) will surely find, definitely go ahead and send it back while you can. For the most part they do seem to eventually get thing sorted out, however its not something I would count on to happen for sure. -
Hmm... i am still tinking about which device would be better.
The Maynuo seems to support only CC-Operation in List mode.
The Rigol supports CC, CV, CR, CP-Operation in List Mode.
Actually i am waiting for an answer from the support people if there is a user calibration procedure for the rigol available/possible.
The Rigol PC-Software (Ultra Load) for remote access looks fine to me as a control-software. But it seems that it is not able to store the graphs recorded and even the date can only be stored as CSV. Maynuo supports an internal formad and exports to excel and word. Also it is not possible to make some graphical cursor measurements as with Maynuo. And it seems to be not possible to use the tests from the software. This makes the software nearly useless. One aspect of modern devices is that it must be possible to store data for later use. Or is there some feature hidden for my eyes in this software?
Another aspect i am thinking about: Rigol wants the Rise-Time setting entered as a Slew-Rate, Maynuo as the time itself. In many cases the slew-rate entry needs some calculation.
And Rigol misses the LED operation. But this is something i do not need currently. -
The Maynuo seems to support only CC-Operation in List mode.
On a device yes..
From software, in Program tab, you can program steps in all 4 modes... Also, in Autotest tab, you can program in MIXED modes in every step,measure and create pass-fail criteria, log results to a database, make reports and export to Excel and Word.. -
On a device yes..
From software, in Program tab, you can program steps in all 4 modes... Also, in Autotest tab, you can program in MIXED modes in every step,measure and create pass-fail criteria, log results to a database, make reports and export to Excel and Word..
Ah, i see, thank you for that hint. In Autotest it is available and the List mode uses the setting that has been selected on the "Main Panel".
Do i interpret the list mode settings and the Graph correctly, the device will not "jump" from one current value to the next at the end of the delay time, instead it will make a smooth and floating transition? -
Do i interpret the list mode settings and the Graph correctly, the device will not "jump" from one current value to the next at the end of the delay time, instead it will make a smooth and floating transition?
Unfortunately, no, it is step transitions, but you can have hundreds of steps and arbitrary resolution, so you can approximate linear ramps .. -
Unfortunately, no, it is step transitions, but you can have hundreds of steps and arbitrary resolution, so you can approximate linear ramps ..
Mhh... maybe a feature comparison table could be a good idea for my decision. Why didn't rigol make a device that is better in every aspect than the competition (which sells devices that are several years old). They have several interesting small ideas implemented that i cannot find in the Maynuo, but is it worth to buy Rigol when there are some disadvantages on the other end of the table?
Actually i am thinking about the isolation of the rear bnc-output for current/voltage monitoring of the DL3000. It would be nice if it is isolated (but i am assuming that it is not).
Also i could not find any exact information if the DL3000 rear Voltage monitor output reads back the Input or the Sense Terminals when they are in enabled.
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I have a Maynuo DC load, but I can't use it when measuring noise on the DC line because the load inject a lot of noise. I think I remember an episode of Daves video with the BK Precision that had the same problem. Anyone knows if this unit is usable for noise measurements of power supply under load?
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I have a Maynuo DC load, but I can't use it when measuring noise on the DC line because the load inject a lot of noise. I think I remember an episode of Daves video with the BK Precision that had the same problem. Anyone knows if this unit is usable for noise measurements of power supply under load?
Are your observations similar to the ones described here?
https://www.eevblog.com/forum/testgear/dc-electronic-load-induced-noiseq/
Interesting to see: some Series of the Maynuo Loads (I.e. M88-Series) do have ripple/noise information in their specs. I could also find information in older agilent DC load datasheets, but none in the Rigol documentation.