ADP3250 calibration

[nakajii]

Hi,
 I am confused by the results of the DC voltage accuracy check using the "Wavegen" and "Logger" functions of the calibrated ADP3250 and the Keysight's DMM U1272A. Is there anything I can do to fix this?　Please give me advices.
Situation:
 DC values  on the "Logger"-"C1.DC" were 30mV to 50mV higher  and "C2.DC" was about 400mV higher than the "Wavegen"-"DC"-"Offset " setting.
 The above shifts were found regardless of the voltage level when checking from low to high levels, but the U1272A's  value were almost correct. There is no functional problem other than the shift of the probe's measurement voltage.
 These shifts are not small and seem to indicate that something is wrong with the calibration.  
I have run the calibration according to the "Wizard" after warming up for 1 hour, and even "APPLY". The voltmeter I referred to is the U1272A mentioned above.

[JColvin]

Hi @nakajii,

I have moved your question to a more appropriate section of the Forum.

I don't know your exact setup, but the Logger instrument by default uses the Low gain / full range of the Analog inputs, so for more accurate measurements you would need to make sure you using the 5 V range (adjustable through the "Gear More" dropdown next to the update rate). I presume you already connected the grounds between the devices for good measure.

Other potential sources of error that I could think of would be that the BNC probes are not set to 1x attenuation, or that you are using a BNC probe on the Wavegen output rather than just a BNC passthrough cable that has no additional circuitry.

Let me know if I have misunderstood your setup.

Thanks,
JColvin

[nakajii]

Hi JColvin

Thanks for the advice.

>>>using the 5 V range (adjustable through the "Gear More" dropdown next to the update rate).

I don't see a 5V range there, but I will set it to "maximum" and take a measurement.

>>>the BNC probes are not set to 1x attenuation

My probe was set upped X10.

　I will measurement and post later.

Nakajii

[attila]

Hi @nakajii

The oscilloscope inputs on ADP3X50 have 50 and 2V pk2pk rage.
At low range the resolution and precision are better.

[nakajii]

Hi JColvin, attila.

Thank you very much for your advice the other day.
My ADP3250 seems to have returned to almost normal operation.
Below are three reports and one question.

Report 1:.
 I summarized again the situation with the Wavegen DC offset setting and Logger detection voltage on the ADP3250 at the time of my first post. I cut the offset setting voltage below 0.01V because the measured values were so out of control that averaging data processing was meaningless.

 

Report 2:.
  While researching and trying to find a way to reset the ADP3250, the following operation improved the large shift shown in report 1 above.

  (1) "Device manager" -> "Calibrate" -> "Reset" -> "Load Factory"
     ==>The situation remains the same with no return to the initial state and a large shift in C2.

  (2) "Device manager" -> "Boot" -> "Standard Recovery"
       "Device manager" -> "Calibrate" -> "Reset" -> "Load Factory"
     ==>Close to the memory of the situation at the time of purchase.

  (3) "Device manager" -> "Calibrate" -> "Wizerd"
     ==>The shift in C2 is smaller and the values of C1 and C2 are almost identical.

  "Device manager" -> "Boot" -> "Standard"
  ==> Measurement for Rport 3

Report 3:.
   After Report 2, Calibration is performed again and the results of accuracy measurements are reported.
 3-1: Logger Range 2V, Probe x1
 Accuracy approached that of the specification.

 

 3-2: Based on JColvin's explanation, directly connected with BNC cable and T-joint for measurement.
 Almost same as measurement result in 3-1. no problem with BNC probe in 3-1.
 

 3-3: Based on JColvin and attila's explanation, evaluate the degree shift with x10 probe
 The shift is roughly 10 times larger than the original C2 shift level, but we have confirmed that this is a significant improvement from the original C2 shift level.

 In conclusion, my ADP3250 seems to have returned to almost normal operation.

Question:
In electronic equipment, procedures such as "Software Reset" and "Hardware Reset" are often given for abnormal operation.　I have tried to do the operations described in report 2 above, but if there is a correct procedure, please let me know.

Thank you,
Nakajii

 

[nakajii]

Hi JColvin, attila.

I'm sorry. graphs deleted.

Report1:

Report3;

3-1

3-2

3-3

thank you 

[JColvin]

Hello,

The reset operation you described in 2-1 ("Device manager" -> "Calibrate" -> "Reset" -> "Load Factory") is the correct method to change the calibration values to what the ADP3250 was loaded with during the manufacturing process.
If the factory calibration results are not satisfactory, then the first half that you described in 2-3 ("Device manager" -> "Calibrate" -> "Wizard") is the correct method to adjust the calibration values as needed for your particular unit.

Choosing the different Boot options is not needed for changing calibration values. As per the Help Tab documentation for the ADP3450/ADP3250 in the Boot Mode section, whenever the device is powered on from the off state, the Standard Recovery is started by default and then automatically transitions to either the Standard or U-Boot (Linux Mode) applications, depending on what has last been selected by the user.

Let me know if you have any questions.

Thanks,
JColvin

[nakajii]

Thanks JColvin.

The system is now back to sufficient accuracy and I will restart using it.

If the situation becomes mysterious again, please let me ask a question.

nakajii