Author Topic: Hantek 2000 series - 2C42/2C72/2D42/2D72 (Read 131336 times)

gf · « **Reply #75 on:** March 04, 2019, 10:56:12 pm »

Quote

I did some measurements in single channel mode (with -70...)

Was the "70" patched in the firmware? Or in other words, which model was it natively?

Thanks,
gf

JimBeam · « **Reply #76 on:** March 05, 2019, 06:41:20 am »

My device is a native 2C42 with the -70 patched in flash.

I used a R&S SMIQ03B Generator for the DSO tests set at 0dBm output and a 50 Ohm feedthrough termination on the DSO inputs.
The AWG output was observed on a RIGOL DS1104Z with the same cable setup reversed.

I will repeat the AWG measurements more exactly when time permits, maybe using a DSA702 to record the spectrum,
but I'm not expecting miracles anyway as the 2000 series are devices in the low price segment.
HANTEK even replaced the intended inductors on the board by 0 Ohm resistor to cut prices...
Yet they were so nice to retain a lot of the parts in the AWG that would not have been necessary to keep.

The presence of the AWG section is simply detected by R65

This is the DAC enable signal from the FPGA forwarded to the MCU via R65.
The chosen value of 560 Ohms is just my educated guess, some russian guy in a YouTube video used 50 Ohms.
Maybe someone with a genuine 2Dx2 could confirm the real world value of R65? The pictures in this thread are too blurry to read the marking.

Quote

In my 2D72, the negative rail of the EL5166 measures rather about -3.3V

The mentioned -4V for the -5V rail were just from memory, I did not note the exact value.

When I saw the clipping I looked for a cause, found the -5V not being 5V, checked the feedback divider resistor values in the supply - and modified them without any hesitation.

Btw.: Being at it, I retrofitted the SD card holder - to no avail. I guess there is no support in the SW.

JimBeam · « **Reply #77 on:** March 05, 2019, 06:37:35 pm »

I just did some calculations around the DAC:

With an R_set of 2,2k we get a fullscale output current of around 18mA, which results in a voltage drop of about 0,9V across the 50 Ohm output load (This disregards the input impedance of the OpAmp input dividers, but as I used 51 Ohm resistors anyway, the difference should be neglectible.)
As the gain of the output driver is 3,733 (560/150 Ohm) the fullscale output voltage at the BNC (without load) is 0,9V * 3,733 = +/- 3,36V.

So the DAC range isn't fully used - or is there a mistake in my calculation?

gf · « **Reply #78 on:** March 05, 2019, 08:20:30 pm »

Quote from: JimBeam on March 05, 2019, 06:41:20 am

The presence of the AWG section is simply detected by R65 This is the DAC enable signal from the FPGA forwarded to the MCU via R65.
The chosen value of 560 Ohms is just my educated guess, some russian guy in a YouTube video used 50 Ohms.
Maybe someone with a genuine 2Dx2 could confirm the real world value of R65? The pictures in this thread are too blurry to read the marking.

I have a genuine 2D72. I have attached a photo of the (non-existing) R65

gf

JimBeam · « **Reply #79 on:** March 05, 2019, 08:28:00 pm »

Ooops, that's the wrong R65 ...
I mean the one marked in the attached picture. (I hope Microcheap forgives me "borrowing" his picture from reply #38)

gf · « **Reply #80 on:** March 05, 2019, 08:35:43 pm »

I'm adding photos of the two major AWG "regions" on the board (including the marked resistor).

69B = 5.11k

gf

JimBeam · « **Reply #81 on:** March 05, 2019, 08:43:06 pm »

Ahh, that's perfect!! THANK YOU VERY MUCH, gf

That means R65 is 5,11k (EIA-96 code 69B).

Edit: I overlooked, that you already wrote the value, so my comment was superflous. I should read post from the beginning to the end - but I was attracted by the pictures before reading...

gf · « **Reply #82 on:** March 06, 2019, 12:11:39 am »

Quote from: JimBeam on March 05, 2019, 06:37:35 pm

I just did some calculations around the DAC:

With an R_set of 2,2k we get a fullscale output current of around 18mA, which results in a voltage drop of about 0,9V across the 50 Ohm output load (This disregards the input impedance of the OpAmp input dividers, but as I used 51 Ohm resistors anyway, the difference should be neglectible.)
As the gain of the output driver is 3,733 (560/150 Ohm) the fullscale output voltage at the BNC (without load) is 0,9V * 3,733 = +/- 3,36V.

So the DAC range isn't fully used - or is there a mistake in my calculation?

a) The voltage gain is lower than 560/150, since you neglected the 50 Ohm resistor.

b) On the other hand, the voltage gain applies to the voltage difference between the DAC outputs, which is higher than the single-ended AC voltage between one ADC output and GND.

c) Just applying a factor of 2 - in order to account for (b) - would not be valid either, since the AC voltage is not the same at both ADC outputs, because the current sources drive into different impedances. The inverted output of the DAC (leading to IN+ of the amp) is terminated with (50 Ohm || (150+560 Ohm)) == 46.7 Ohm towards GND, but the effective termination impedance of the non-inverted DAC output towards GND is affected by the feedback from the amp output, and is lower.

EDIT:
A more detailed analysis/calculation of this kind of ADC termination circuit can be actually found e.g. here: http://www.ti.com/lit/an/sbaa135/sbaa135.pdf. They also don't consider voltage gain, but rather transimpedance of the amp, as the inputs are current-driven. Quote from this paper:

Quote

...This relatively simple-looking circuit is, however, not giving a matched gain nor a matched input impedance for the two current source outputs...

Anyway, I share the conclusion that the DAC not fully utilized. But it may make sense to leave a couple of percent headroom for gain/offset adjustments in the digital domain.

(1) DC bias measurement:

On my board, Rset = 25B = 1.78k (not 2.2k). If the IC were a DAC902, this would correspond to I_OUTFS = 22mA. However, it is not a genuine DAC902, but a chinese chip with unreadable markings and unknown specs. So we can only guess. At least it seems to be plausible that the specs are similar.

When I select the "Arb4" signal (-> eventually DC with 50% digital count of full-scale), then I measure about 500mV DC each at the inverted and non-inverted DAC output pins, and the EL5166 output is about 0V (all readings against GND). At this bias point, each DAC output is loaded with 50 Ohm || (150+560 Ohm) == 46.7 Ohm towards GND. 500mV / 46.7 Ohm = 10.7mA at each output, and this is indeed pretty close to the predicted I_OUTFS / 2. Looks reasonable

(2) AC measuremt:

For simplicity it is IMO sufficient to consider only the AC current at the inverted DAC output whose termination impedance is not affected by the amp feedback (-> the AC current at the other DAC output is supposed to be the same, just inverted). With the AWG set to a square wave with an amplitude of 2.5V, I measure 870mVpp at this ADC ouput. 870mVpp / 46.7 Ohm = 18.6 mApp. And yes, that's only about 85% of I_OUTFS.

[ My 6074BD scope is not so accurate, though, so please grant sufficient tolerance to my measurements. ]

gf

gf · « **Reply #83 on:** March 06, 2019, 08:46:14 pm »

Follow-up to my previous message:

I calculated the gain accodring to the TI paper (neglecting beta), based on the nomimal resistor values on the board, and I get a total transimpedance of 280 Ohm (or in other words 280 mV/mA), where 280 = 50*560/(50+150)*2. I.e. 20mApp DAC current corresponds to 5.6Vpp at the opamp output (if there weren'n the clipping, of course).

I also tried to determine the DAC's I_OUTFS a bit more exactly. The voltage at Rref measures 1.11V, which is obviously lower than DAC902's internal reference voltage of 1.24V. There is no voltage at the REFin pin (DAC902 were supposed to ouput the buffered internal reference voltage here, if I understand the block diagram correctly). I can't measure the 1.78k Rref in-circuit - some of the current seems to bypass the resistor via a different path - so I take the marked value as granted. This leads to a predicted I_OUTFS of 1.11/1780*32, i.e. almost exactly 20mA.

The termination of the DAC's Iout- to ground measures 47.1 Ohm (nominally calculated was 46.7).
And With "Arb4" waveform (-> 0V DC signal), I read a voltage of 467mV at Iout-. That's an Iout- of about 9.92mA.
Iout+ splits up into 9.4mA to ground (through 50.1 Ohm) and 0.67 mA through a 150 Ohm resistor to the opamp's IN- pin.
So Iout+ is about 10.1mA, and the sum of the DAC's measured Iout- and Iout+ currents is almost exactly 20mA as well.

The nubers fit reasonably with each other.

If the reference voltage of your genuine DAC902 is actually 1.24V, as specifiled in the datasheet, then you likely need a slightly larger Rref (1980 Ohm), in order to get an I_OUTFS of 20mA as well.

I'm also not sure, whether some calibration data (gain/offset correction) are stored in the device's flash. If they do exist, then they are certainly missing or incorrect in an "upgraded" 2Cx2. The notceably different I+ and I- currents measured with "Arb4" signal suggest that a digital offset correcetion may have been applied, since the measured voltage at the opamp output is indeed as low as 2.5mV, when it is supposed to be zero.

EDIT: I'll try to measure the digital count at the ADC data lines as well, which lead to the observed output, but I guess it's not 2048.

gf

gf · « **Reply #84 on:** March 07, 2019, 08:00:16 pm »

@JimBeam:

I have now also measured the digital values sent to the DAC for 0V, 2.5V and -2.5.

Set voltage	Digital DAC input value	Measured voltage at EL5166 output
0V	2062	2.5mV
2.5V	238	2.49V
-2.5V	3886	-2.50V

=> I.e. from the range 0...4095, the sub-range 238...3886 (5.8%...94.9%) is utilized on my device in order to generate -2.5...+2.5V output voltage.

The digital values are so weird that I'm now almost sure that they are different on each device, depending on its individual calibration.

Btw, obviously lower digital values represent higher output voltage, because IN+ of the amp is fed from the DACs I_OUT-.

And 2062 also happens to be (3886+238)/2 (as expected)

.

EDIT:

Btw, I'm surprised that there was no clipping at -2.5V. But this was measured w/o load. With 50 Ohm at the AWG output, the voltage drops to -2.39V. Also measured my EL5166 supply rails again => -3.41V and 4.92V.

gf

electedfx · « **Reply #85 on:** March 11, 2019, 07:15:32 am »

Gday, guys! Owing Hantek 2D72 and experienced a dfu update failure, now device is bricked, do not respond on a power button. Found out, that it can be solved with flashing via st-link. If anybody have an full dump for 2d72, pls help. Also looking for a manual how to program it and a way to save calibration values. Thank you in advance.

gf · « **Reply #86 on:** March 11, 2019, 08:08:36 am »

I never had the need to try it, but maybe this helps:
https://www.eediscuss.com/forum.php?mod=redirect&goto=findpost&ptid=14722&pid=17849
The download seems to include the bootloader and instructions.
Download soon - link expires tomorrow.

gf

electedfx · « **Reply #87 on:** March 11, 2019, 08:13:30 am »

Downloaded it already, will make a try later.

electedfx · « **Reply #88 on:** March 11, 2019, 06:31:18 pm »

Many thanks! Finally recovered the device from brick with your methods, now need to downgrade to previous firmware wgere AWG works.

Crimson · « **Reply #89 on:** March 11, 2019, 10:48:27 pm »

Quote from: electedfx on March 11, 2019, 06:31:18 pm

now need to downgrade to previous firmware where AWG works.

Wait, are you saying that AWG doesn't work on the newest firmware? Or it's just not working because you flashed the wrong version or what? I was planning on flashing the newest firmware this evening but if it causes AWG to stop working I guess I'll stick with what I've got.

Microcheap · « **Reply #90 on:** March 12, 2019, 12:16:21 am »

Quote from: Crimson on March 11, 2019, 10:48:27 pm

Wait, are you saying that AWG doesn't work on the newest firmware? Or it's just not working because you flashed the wrong version or what? I was planning on flashing the newest firmware this evening but if it causes AWG to stop working I guess I'll stick with what I've got.

Yes it does works, there are some other issues that are not software related though that we are discussing here: https://www.eediscuss.com/forum.php?mod=viewthread&tid=14705&extra=

I am using the latest version (20190030201) that already fixed some bugs and you can get from https://www.eediscuss.com/forum.php?mod=redirect&goto=findpost&ptid=13676&pid=16428 and follow the instructions to install it. Hantek promised another update for the next few days.

sega · « **Reply #91 on:** March 15, 2019, 06:12:25 am »

Hello, a suspicious situation, the manufacturer claims that the 12bit generator, but put dac 3PD5651E 10bit and erases the markings on the chip. How can it be, this is a Scam, what kind of DAC chip was planned and should stand? Maybe it was planned DAC902E (12bit) TI/BB?

Pinkus · « **Reply #92 on:** March 15, 2019, 08:51:04 am »

How comes you are suspecting that there is only a 10 bit DAC used? Any evidence?
At least Bit 11 and 12 (D0 and D1) are connected to the chip. Maybe somebody can just measure if there are signals on Pin 11 and Pin 12 of the DAC? If yes, all 12 bits are used as the mentioned 3PD5651E does not use these two pins.

gf · « **Reply #93 on:** March 15, 2019, 09:52:27 am »

Were you able to read the marking? Are you sure that it is a 3PD5651E? AFAIK, this was just a speculation so far. On my 2D72's chip "...EAK" is vaguely recogizalbe, so 3PEAK is likely the manufacturer, but it could be a non-public custom chip made for Hantek.

gf · « **Reply #94 on:** March 15, 2019, 10:05:13 am »

Did a brief test. Near zero, I can distinguish quantization steps of roughly 1.5mV at the output, so IMO it is 12 bit.

sega · « **Reply #95 on:** March 15, 2019, 10:34:51 am »

3PEAK makes a 12bit DAC in a TSSOP-28 case? Why is the markings on the hull erased?. Read about the DAC on the forum.
MCU: STM32F103VET6
ADC: AD9288BSTZ-40
FPGA: LATTICE XO2-1200U
DAC: 3PD5651E
DMM (multimeter): CS7721CN-1
OU amplifier at the output of the generator (put different): EL5166, LMH6702
Near Oh the missing SOT-23: BAV 99

gf · « **Reply #96 on:** March 15, 2019, 12:39:32 pm »

Given a DAC range utilization of about 90% (some headroom for gain/offset calibration), 5Vpp AWG output voltage and 12 bits, one LSB step calculates to about 1.36mV. For 10 bits, the resolution would be only 5.43mV. How could I measure a resolution of better than 1.5mV at the output if it were only a 10-bit DAC? I have absolutely no doubts that at least the DAC in my genuine 2D72 does resolve 12 bits.

[ I do not trust the fractional millivolts displayed by my DMM, but it still can clearly distinguish ~5.5mV steps from ~1.5mV steps in its 200mV range. On my other scope @ 2mV/div I can clearly distinguish these magnitues as well, despite 500uVpp noise. ]

EDIT:

For better accurracy measured once again with scope, now using 64x averaging acquisition, and let the scope display the avg voltage along the timeline. One of the DAC steps reads 5.00mV, and the subsequent one 6.37 mV. The difference is pretty close now to the calculated 1.36mV.

Btw, there is one observable similarity to the specs of the 3PD5651E:
The voltage at Rset measures 1.11V. The 3PD5651E has a specified internal reference voltage of 1.1V, while DAC902 has 1.24V.

But there is also a difference to both, 3PD5651E and DAC902:
Both were supposed to output the reference voltage at pin 17, but there is no voltage on pin 17.

The required minimum setup and hold times of 2ns+1.5ns given in the 3PD5651E datasheet were IMO too large for 250MSPS operation either -- this would leave ony a window of 500ps where the data are allowed to change - I doubt that the FPGA can fulfill this. Even the typical setup and hold times given in the DAC902 datasheet of 1ns+1.5ns are already pretty tight, but would at least grant a window of 1.5ns for the data to change (but still challenging). Well, maybe this is even the cause for one of the nasty problems with this AWG. I have some evidence that the origin of the spikes/glitches might be on the digital side of the DAC, but not sufficient evidence to prove or disprove it (don't have fast enough equipment to measure the timing on the DAC inputs and clock).

NovoTemp · « **Reply #97 on:** March 28, 2019, 12:17:01 am »

Hello, friends.
I need to check AC wave form from power outlets (AC 220V) at home.
Can I do it with Hantek 2D72? Is probes is suitable for it? I need to use 1:10X position?
Please advise.
Best regards.
Awaiting your soonest reply.

1937 · « **Reply #98 on:** March 30, 2019, 11:46:03 pm »

Saw empty seat places on the board and I asked the developers to add software support for the micro sd card and wi-fi module on this page:
https://www.eediscuss.com/forum.php?mod=redirect&goto=findpost&ptid=14668&pid=18035&fromuid=28755
I think it could be useful to save the waveform images directly to tf-card in the device or to receive data from the device via a wireless line.
If someone will support my idea on the eediscuss.com forum, it would help in its implementation.

gf · « **Reply #99 on:** March 31, 2019, 08:26:42 am »

Quote from: NovoTemp on March 28, 2019, 12:17:01 am

Hello, friends.
I need to check AC wave form from power outlets (AC 220V) at home.
Can I do it with Hantek 2D72? Is probes is suitable for it? I need to use 1:10X position?

Hantek's PP-xx probes are rated 600V peak when the switch is in x10 position.
http://www.hantek.com/en/ProductDetail_73.html

And the input protection voltage of the 2000 series' scope is specified with 150V in the handbook, which is not supposed to be exceeded either when probing a 230V RMS sine wave with an intact 10:1 probe.

If there were any significant overvoltages (say 1000V spikes) on the power line, then you would exceed these limits, though.

Please don't blame me if Hantek doesn't meet their specs - it's up to you whether you do trust or do not trust the spects.

[ Btw, be careful and keep in mind that 230V mains are potentially lethal. If you don't trust the probe's insulation, then don't touch ground, but keep your body insulated from ground when you touch the hot wire with the probe tip, in order that no current can flow through your body. ]


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Author Topic: Hantek 2000 series - 2C42/2C72/2D42/2D72 (Read 131336 times)

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