Author Topic: New Rigol DC Load DL3000 Series  (Read 48402 times)

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Offline simone.pignatti

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Re: New Rigol DC Load DL3000 Series
« Reply #150 on: October 13, 2017, 10:46:12 am »
Hello, sorry if I couldn't post before but I was on a biz trip
We have checked the units in our stock and here is what is included. It seems the certificates are inside.
Technical Support
 

Offline MotoDan

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Re: New Rigol DC Load DL3000 Series
« Reply #151 on: October 18, 2017, 05:15:15 pm »
Had to give up on Rigol trying to address the problems with the DL3021A within my 30 day return period. Time to move on to a DC load that is ready for use. Maybe the DL3000 series loads will be better with some future code and hardware changes that address the unit's shortcomings.
 

Offline TurboTom

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Re: New Rigol DC Load DL3000 Series
« Reply #152 on: October 18, 2017, 09:23:50 pm »
...did some more testing of the DL3021 last weekend and as MotoDan reported, the instrument should probably have undergone some more testing at Rigol´s labs before being released to the public.

Here´s the setup I used:


Basically I stacked a lot of Rigol gear on the bench (Power supply @ 20V / 10.5A, Oscilloscope, MOSFET switch, function generator to provide a square wave gate drive to the MOSFET @ 2kHz) and added my Maynuo load as a "spacer" to compensate for my venerable Tek P6042 current probe.

The current probe is connected to trace 2 (the cyan one) of the scope while trace 1 (yellow) displays voltage at the load terminals or across the MOSFET (as shown in the video further down).

I started testing the load at low currents and especially kept an eye on manual on/off behavior and automatic toggling. Here´s what I found:



Manual on @ 100mA - a lot of "bouncing" and quite high initial current @ almost 1.4A. See below with a different time base.



Once the average current has stabilized, there´s a residual oscillatioin of 50mApp @ 4.7kHz:



If the load is toggling the current internally, the overshoot gets  a little better but the oscillation is still there. Once again CC 100mA , first toggle frequency 100Hz and directly below 1kHz:





After this, I checked the performance of the constant voltage mode (CV), adjusted the load to 10V and the PSU to 12v and connected an 18Ohms resistor in between (like a classic zener diode circuit). The speed the DL3021 needed to settle is more than disappointing. It appears the load is emulation this mode with the passbank still in current mode while the digital circuitry slowly adjusts the current to provide the proper voltage drop. It takes round about 2.5 seconds for the voltage to finally settle. Unfortunately i forgot to cross-check this with the Maynuo load:



After that some more constant current testing at higher settings was due. 10A CC manual on:



The small spikes that start approx. 5ms before the current rises indicate the instance I pressed the "Load On" button. Rigol, WHY??!  ::)

Now I tested some fast internal toggling @ 10A, frequencies in sequence 1kHz, 5kHz and 10kHz:







The optimist´s comment would be "at 1kHz it looks half-way okay..."  ;)

Rising and falling edges @ 10A and 100Hz internal toggling:






After that, I started what I expected to get ugly: Switching the current to the load externally with the MOSFET. Since the source of the MOSFET had to be ground-referenced via the square wave generator, I couldn´t probe the voltage across the load anymore (actually I could have by wiring the load at the FET´s source and probing at its negative terminal and inverting the channel on the scope but I didn´t consider this at the time...was somewhat in a hurry) so the voltage across the MOSFET is displayed. Setting was 1A CC, low frequency (about 10Hz) recorded at two different time bases





I guess the inrush current is much higher than the 23A displayed here due to saturation effects of the TEK current probe.
BTW, the Maynuo load doesn´t perform much better in this test (no screenshots available).

Things don´t change at higher frequencies, here 1A CC, 1kHz externally switched:



At higher currents the load appears to perform slightly better, here 10A at 2kHz are shown. But still no stellar performance.




Finally, I left the load running in CC mode, externally switched by the MOSFET and continuously varied the current setting. Now some very strange things happened, see here:

http://www.turbinemuseum.de/files/DL3021/DL3021-Test1.mp4

It seems the DL3021 (can´t tell for the other versions but I assume they perform likewise) is designed for rather high power applications and somewhat fails at the low settings. It appears only the constant current mode is implemented in hardware and CV (didn´t test for CR and CP modes yet) is a software-controlled function that shows a very slow reaction to input changes. This also explains why Rigol only implemented the internal sequencing/toggling functions for CC mode. If this is true, I doubt that a firmware upgrade could change this. Considering all these shortcomings, a return-option in case of a purchase should be well considered unless the owner relly needs the load only for rather slow high-power testing.

Cheers,
Thomas



 

Offline TurboTom

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Re: New Rigol DC Load DL3000 Series
« Reply #153 on: October 20, 2017, 11:32:22 pm »
Sorry for the direct follow-up, but I just had to do some more testing of the load and unfortunately - though not unexpected - things get even worse:

I had a closer look at the dynamic behavior of CV, CP and CR modes. This time I also did some more measurements on my Maynuo M9712 load for comparison. My setup is basically the same that I used in my previous contribution, I only wired the voltage probe so it displays the voltage across the load this time.

So let´s start with the Maynuo which more or less performs as expected:
Here's the CV mode at 50Hz external switching frequency, 18R series resistance with the power supply:



And the same thing at a different timebase setting:



The voltage settles at somewhere between 2.5ms and 4ms. Not particularly fast but that´s probably what one could expect from an "el-cheapo" electronic load. Usable at least...

I then changed the load to constant power mode (CP) at 10W, 50Hz, once again two different timebase settings:





The behavior is not perfect, it takes the load some 350µs to recognize that there´s a voltage present and to cut down the current/raise the resistance of the passbank but then it settles pretty quickly at the expected figures. Once again, no real reason to complain considering the price.

Finally the last test with the Maynuo in CR mode, 20Ohms selected and once again externally cycled at 50Hz:





What else can I wish for - the proper current is flowing 600µs after the external voltage has been applied. Virtually no droop or whatever can be observed. Well done, Maynuo!


After these tests, the DL3021 was due, and what should I say -- in some cases, I cannot even interpret my findings. In general it seems that Rigol ATTEMPTED some "adaptive" parameter matching but I would say there´s still a considerable distance of road for Rigol to travel in order to come up with a useful result. I tried to duplicate the tests I did with the Maynuo M9712 load before but it turned out that in most cases, the frequency setting of the externally applied power that I used for the Maynuo was just too much for the DL3021. So here we go, first test CV mode @ 10V, 18Ohms in series, 1Hz at two timebase settings:





The load needs some 200ms to settle within 5% of the selected voltage. It´s quite curious that the slope doesn´t seem to be an expenential decay but it rather seems to take much longer in the end to actually reach the preset voltage level. The 1Hz period of the externally applied signal doesn´t suffice to achieve that.

During the next test, things turned out really awkward -- in CP mode (10W), I found the load not to reach any steady condition if I toggled the external supply with 50Hz:



The load kept on modulating the power drawn at a slow pace. It seems the internal "optimization" routine was completely overtaxed. But things turned out even worse in the consequent test: I changed the external toggle frequency to 1Hz in order to permit more time to for the load to catch up -- which may not have been a good idea: After several seconds of operation in a rather unstable manner, the load shut itself down with an error message similar to "Overcurrent detected, input shut down" or the like (don´t remeber the phrase exactly). At least here´s a screen shot of the things going on:



Hint: Don´t take the current displayed before shutdown to be correct -- it´s well possible that my current probe was satuated by the current drawn by the load that was much higher than that. This may also correlate with the warning message on the screen of the load.
Finally, here´s an enlarged sceen shot at the load´s input. Why did it change the current to 1.6Amps after it adjusted to the proper current (0.5A) initially?



And here we are with Rigol´s CR mode, crap as well... (sorry, tried to stay neutral but getting disappointed more an more...  :-[). Load adjusted to 20 Ohms and externally toggled at 1Hz. Funny thing is the current "approximates" to (almost) the final value of 1A over several periods (something like 25...50) and then suddenly settles at the proper value and stays there (as far as I can tell) as long as the load isn´t switched off:



Funny thing, at 50Hz toggle frequency this won´t work -- the modulation continues until I was tired to wait any more:



And the final test  @ 10Hz showed the settling again, yet with considerable overshoot in between. It also took the load a considerable time to reach that "steady-state" that´s visible at the right of the screenshot:



If you now ask me about my opinion regarding this instrument, I'ld put it like that:
If Rigol was a car manufacturer that´s only half-way respecting themselves, they should call back ALL of their DL3021 (probably all of the DL3000 series) loads sold so far and refund their customers in full, regardless of their distributor´s offerings. This product isn´t up to meet the market yet. If Rigol doesn´t act like that, flush them down the drain. They have got quite some acceptable equipment but this load is not ripe to be supplied to the public. It´s a shame to have their customers doing the job their "alpha-testing department" should have done. I sincerely hope someone who´s got some authority at Rigol reads these lines and provokes corrective actions. I´m almost certain that the shortcomings of the load cannot be all corrected by a software update but rather need a revised hardware.

I defintely recommend not to spend the money on that load - the internal features don´t differ too much from the aesthetics of the front panel -- unfortunately!

Cheers,
Thomas

Offline nugglix

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Re: New Rigol DC Load DL3000 Series
« Reply #154 on: October 21, 2017, 08:16:32 am »
Thanks for the testing done.
Saved me some money.  :phew:
So going to look at the Maynuo...
 

Offline TurboTom

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Re: New Rigol DC Load DL3000 Series
« Reply #155 on: October 21, 2017, 05:30:38 pm »
It seems Rigol is taking their new company slogan "Innovation or nothing" for real -- this time it was the latter  ;)
 

Offline Rbastler

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Re: New Rigol DC Load DL3000 Series
« Reply #156 on: October 21, 2017, 05:40:01 pm »
Glad I went for the Maynuo  :phew:
http://rbastlerblog.jimdo.com/
Gamma spectrometer works. Now some yellow crystals need regenerating and testing.
 

Offline bitseeker

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Re: New Rigol DC Load DL3000 Series
« Reply #157 on: October 21, 2017, 07:47:34 pm »
Thanks for all the tests, Thomas. Great job. :-+

This bit at the end pretty much sums it up: "the internal features don't differ too much from the aesthetics of the front panel."
I TEA.
 

Offline purpose

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Re: New Rigol DC Load DL3000 Series
« Reply #158 on: November 06, 2017, 02:26:26 pm »
I just found that I could wind my 3021 up to a 350W load... I would have thought it might have kicked me off way before then.
I feel a population of the extra gizmos creep over me.
 

Offline MTNELECTRONICS

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Re: New Rigol DC Load DL3000 Series
« Reply #159 on: November 07, 2017, 12:10:40 am »
I just found that I could wind my 3021 up to a 350W load... I would have thought it might have kicked me off way before then.
I feel a population of the extra gizmos creep over me.

Interesting...how long until it blows?     :palm:

I noticed that on Dave's video you could see that on the 3021 it was allowing him to set the upper current limit to 60A.  Can yours do that and actually turn on?   
 

Offline purpose

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Re: New Rigol DC Load DL3000 Series
« Reply #160 on: November 07, 2017, 06:42:54 am »
Twas only a very brief excursion, but only pulling seven and a half amps, or so.
Current limit can be set to 70A on mine, but can only be set to draw 41.
 

Offline Ice-Tea

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Re: New Rigol DC Load DL3000 Series
« Reply #161 on: November 09, 2017, 07:45:52 pm »
If anyone is interested: I have a Chroma load (6304 + 2 x 63006), would make a nice vid or post to compare the two. So, anyone that is reasonably close and wants to play around with the Chroma or wants to send in their Rigol for a week or two: ping me!

Offline apoorv3in

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Re: New Rigol DC Load DL3000 Series
« Reply #162 on: February 15, 2018, 12:04:07 pm »
Have you tested with new firmware v00.01.02.00.02 2018-1-22

Do you see any improvements.


[Updated Contents]
v00.01.02.00.02 2018-1-22
     - Modified the problems arising from load sinking while being powered on in CR and CP modes.
     - Optimized the overshoot value in CR mode.
     - Modified the record data: originally, the number of the waveform points less than 400 was recorded as 1000, now it is modified to be recorded as Null.
     - Added the Von function in the CR mode and supported Von Latch.
     - Added the cut-off function in the battery discharge mode
     - Added the SCPI commands for the Sense function.
     - Modified the Record function in data recording, capable of recording the four parameters (V, I, R, and P) simultaneously.
     - Modified the List function in data recording, capable of recording the two parameters (V and I) simultaneously.
     - Modified the List operating status error in the SCPI command.


v00.01.01.00.09   2017-08-014
     - Optimize the waveform adjustment mode for Roll and Fast modes
     - Optimize Roll and Fast mode screenshots to support saved CSV format files
     - Roll mode to supports the waveform playback function
     - Roll mode to supports the waveform record function
     - Fast mode supports the selection of voltage and current curves
     - Support CC+CV function
     - Battery mode support W.H units
     - List mode show the results of the last loop after the run completes 
     - List mode support the recording and playback function ( Thumb drive), save the measurement results of each cycle, save the file format to CSV
     - The SCPI command increases the waveform mode adjustment and the readback command of the waveform data


v00.01.00.04.10   2017-04-24

     - Released the first version officially

 

Offline smithnerd

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Re: New Rigol DC Load DL3000 Series
« Reply #163 on: February 15, 2018, 02:36:41 pm »
For those wondering, this seems to only be available from the Chinese version of the Rigol firmware page:

http://www.rigol.com/Support/SoftDownload/3

(replacing hostname 'int' with 'www' - the navigation layout is the same, more or less).

Have you tested with new firmware v00.01.02.00.02 2018-1-22

 

Offline Howardlong

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Re: New Rigol DC Load DL3000 Series
« Reply #164 on: March 06, 2018, 10:05:51 pm »
I blew up my Maynuo M9711 a few days ago, accidentally slapping -15V at 1A from a four quadrant power supply I've been working on was enough to do that: nothing obviously wrong inside, but I don't have the time right now to debug it. Note to self, place a high current schottky across the load's terminals.

So as a replacement, I just received a DL3021A from MCS Test who are currently offering 10% off items in stock over £400. Next day UK shipping was free. (https://www.rigolonline.co.uk/collections/dc-power-supplies/products/rigol-dl3021a-programmable-dc-electronic-load). I won't deny it, the 10% off did push me to the DL3021A, I was going to get the DL3021 and purchase the hires option separately. I don't need 40A, I rarely go above 1 or 2A for my testing!

Anyway, after updating the firmware and having a couple of hours with it I fully concur with TurboTom's post here:

https://www.eevblog.com/forum/testgear/new-rigol-dc-load-d3000-series/msg1318288/#msg1318288

A lot of my work is at the milliamp range, and the current offset, which drifts over time, varies on my example from about 6.5mA to 9mA. The Maynuo also had current accuracy problems at the low end, but not to quite this extent, frustratingly this was a key reason to try a different model: a case of out of the frying pan, into the fire. There are also plenty of software niggles, for example I was trying to a simple 1A on/off cycle but there was a residual 32mA when the load was meant to be off, certainly a software feature. So I guess it's back to a Mosfet and signal generator for this test.

The Maynuo I had only had TTL remote control, so I built myself an FTDI converter, which was OK, but frankly I felt a bit cheapskated that they'd put a DB9 on the back, but only offered TTL levels.

As TurboTom suggests, the UI is far easier to navigate compared to the Maynuo. Having sense connections at the front is also a big plus.

One further thing I hated about the Maynuo on my example was the rotary encoder that was all over the place, it skipped, advanced and decremented, but not necessarily the way you wanted it to, hardly the best for an electronic load. The DL3021A is much better in this regard.

Thing is, the 0.1uA resolution is rendered useless due to the drift and offset. In the short term, once you've negated the offset, the linearity is about 1% between 20mA and 120mA displayed (12.7mA to 113.5mA actual). As the offset drifts, I'd doubt it's fixable in software. The voltage readout is reasonably accurate, 0.3mV off at 5V at 100mA, with or without the external 4 wire measurement (checked with a calibrated HP 34401A).

All in all rather frustrated by the offset, drift and software bugs, but the UI is certainly a significant improvement over the Maynuo.
 
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Offline apoorv3in

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Re: New Rigol DC Load DL3000 Series
« Reply #165 on: March 13, 2018, 02:15:01 am »
My rigol dl3021 keeps crashing in CR mode. The load will stop randomly after which i have to toggle the output again. This issue is more persistant with the rate of input switching. I have installed the latest firmware.
 

Offline sstepane

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Re: New Rigol DC Load DL3000 Series
« Reply #166 on: March 13, 2018, 09:44:13 am »
Hi,

I'm too having some problems with CR mode. Tried support - no luck, they just remain silent and after some time simply close the case. So there is no Rigol support whatsoever. Quite angry -  :wtf: is it hard to reply? Not going to buy any other Rigol equipment.
« Last Edit: March 13, 2018, 10:13:15 am by sstepane »
 

Offline Synthtech

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Re: New Rigol DC Load DL3000 Series
« Reply #167 on: March 13, 2018, 10:09:52 am »
After looking at the comprehensive oscilloscope screen shots above I can see why testing needs to be done to check the transient response of the load during power-up of the load unit and during application of the input current to the load. One question that comes to mind for me is that the Rigol and Maynuo units are sold as DC electronic loads. Isn’t it outside the spec of the units to be applying square waves pulse trains to the inputs?
« Last Edit: March 13, 2018, 10:12:38 am by Synthtech »
 

Online 2N3055

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Re: New Rigol DC Load DL3000 Series
« Reply #168 on: March 13, 2018, 10:19:41 am »
DC load  means it should be used for testing of DC power supplies... And testing can be with static current, voltage, power, or resistance... But one of the tests is PSU behawiour on dynamic, fast changing load. It reveals dynamic response of psu..
 
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Offline bitseeker

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Re: New Rigol DC Load DL3000 Series
« Reply #169 on: March 13, 2018, 07:11:54 pm »
DC is the unidirectional flow of electric charge. Therefore, a square wave (or pulse train) that varies in voltage without changing sign is DC.

Of course, a particular DC load may or may not be able to handle certain forms of DC, which should be defined in its specs.
I TEA.
 
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Offline Worsdier

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Re: New Rigol DC Load DL3000 Series
« Reply #170 on: March 29, 2018, 01:46:04 pm »
Firmware v00.01.01.00.09 added Wh measurements to the battery test program, can someone confirm that it's also possible to select a stop value in Wh? In other words, can I enter a Wh value to discharge before stopping the test, similar to what C_Stop does in Ah.
 

Offline joad

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Re: New Rigol DC Load DL3000 Series
« Reply #171 on: May 20, 2018, 01:10:59 pm »
Hi, I can't find a way to enter a stop value in Wh, I'm using firmware v00.01.02.00.02.

 

Offline Worsdier

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Re: New Rigol DC Load DL3000 Series
« Reply #172 on: May 20, 2018, 01:13:59 pm »
Hi, I can't find a way to enter a stop value in Wh, I'm using firmware v00.01.02.00.02.

Thanks, I guess there is no W-Stop function.
 

Offline MilkmanCDN

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Re: New Rigol DC Load DL3000 Series
« Reply #173 on: June 03, 2018, 02:16:04 am »
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.

This!   I've been looking everywhere for an e-load with an LXi interface.    So far, I've found three:

- Rigol DL3021A - https://www.rigolna.com/products/dc-power-loads/dl3000/
- Kikusui PLZ-5W Series (Very expensive >$5K US) - http://www.kikusui.co.jp/en/product/detail.php?IdFamily=0141
- TTi LD400P (Also expensive >$1.5K US) - https://www.aimtti.com/product-category/electronic-loads/aim-ld400series

I ordered a Rigol and will pick it up in a few days.    My goal has always been to automate SMPS efficiency measurements as it's something that I often have to do.    Performing these manually, especially at different operating points, is painful.

 

Offline ornea

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Re: New Rigol DC Load DL3000 Series
« Reply #174 on: November 09, 2018, 01:01:52 am »
I seem to be having problems using the  SCPI commands below.

The response I get is command error.

I have tried variations on the command with no joy.  Anyone got one of these hooked up to their network by any chance and can check if the command works.

I have no issues querying Volts, Power, watts etc, just the discharge time.

    :FETCh:DISChargingTime?
    :MEASure:DISChargingTime?
    Syntax :FETCh:DISChargingTime?
    :MEASure:DISChargingTime?
    Description Reads the discharge time of the battery.
    Return
    Format
    The query returns a real number
 


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