Comments on: HT-USBee AxPro review

By: Tomi Engdahl

Tomi Engdahl — Mon, 14 Feb 2022 14:56:54 +0000

By: Enrgtech

Enrgtech — Wed, 22 Apr 2020 11:00:44 +0000

The article is much informative which i was searching for .Nice intro good explanation thanks for sharing.

By: Vicky

Vicky — Tue, 12 Sep 2017 03:56:40 +0000

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By: Spa Elixir

Spa Elixir — Thu, 02 Mar 2017 10:13:12 +0000

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By: Ted

Ted — Mon, 23 Mar 2015 17:26:36 +0000

Analog readings completely off. ..

Analog input in ADC (TLC5510I) is pin 19. Range for ADC chip is fixed from 0v (pin 23 REFB) volts to 3.3v(pin 17 REFT). Se datasheet.
3.3v are from output of converter ds1117.
Two op.amps. AD8065 (marked HRA) are for buffering and level conversion with the help of R2,R3 and R28,R29.This op.amsp are connected to +5 and -5v. The -5volts are from 7660 DC converter.

If Va is Analog input from probe. We have:
Vo1 (out of op.amp.U7) = Va x R3 / (R2+R3)
Vo (out of op.amp. U8) = (Vo1 + 3.3)/2 (as the two R28 and R29 are both 1k). This output is connected to pin 19 of ADC.

I see R28=R29=102 = 1k. R3 is 51C = 33.2k, and R2 is 67ohms. And as Sun21 says it is wrong value!

With the wrong value of R2 (67 ohms) we have a -3.3 to 3.3v range…
Changing R2 to 67k we have the expected range from -10 to 10v, for a 0 to 255 counts (8 bit resolution)
and also 100k input impedance !

BSOD: Apps cannot run at the same time on this cypress chip…

By: Sun21

Sun21 — Sat, 21 Mar 2015 17:54:47 +0000

2Serge: in addition to prev. comment: on the board I removed R2 that have _wrong_ value 67ohm (smd label: 80X) and soldered normal (not smd) 68k (smd label would be 80C) into the middle and right holes of RV2.

Now calibration and measurement on the analog channel looks OK. Input R=100k

By: Sun21

Sun21 — Sat, 21 Mar 2015 13:26:22 +0000

2Serge: I have the same device as you: also no U4 and U5 chips.
Voltage is 3 times higher and input resistance=33k on analog input !!!
I added 68k resistor in series and I can calibrate the device and have right measurement on analog channel.

I tested all applications that come with driver, seems work well. But when I tryed to use Generator (output) and Oscilloscope (input) apps at the same time I got BSOD.

By: Serge

Serge — Mon, 16 Mar 2015 08:23:37 +0000

Thank you, Tomi. Unfortunately, my device does not operate properly :(. Analog readings are completely off (9,92V by measuring all above 4,5 V), the analog waveform is the same as digital one.

By: Tomi Engdahl

Tomi Engdahl — Sat, 14 Mar 2015 06:51:06 +0000

Now I added a new higher resolution picture to to end of the posting (click to enlarge).

By: Tomi Engdahl

Tomi Engdahl — Sat, 14 Mar 2015 06:41:54 +0000

That chip U4 in my circuit board is STMicroelectronics 8s003f3p6 8-bit Microcontroller