PGA309 calibrate Issue

Hi Errol,
The customer has updated the software, but the issue is still exist. Is there any other reason for the issue?

Hello Mickey,

Could you send me a screen-shot of the Pre-Cal file GUI, temp ADC,  and the Auto-Cal results after calibration? Also, is the input coming internally from the sensor emulator circuit or from an external source? I will try to reproduce the issue here on my end.

Best,

Errol

Hi Errol,

Look the attachment. It is the EEPROM data at -10C and 25C.

Hello Mickey,

It will be difficult to debug this issue with only the EEPROM data.  Could you please send the following information:

1. Screen-shot of the Pre-Cal file

   

2. Temp ADC

   

3. The Auto-Cal results after calibration

   

4. Is the input coming internally from the sensor emulator circuit or from an external source?

This will help to eliminate variables and find the root cause of the issue.

Thank you,

Errol

Hi Errol,

Please look the attachment. The input signal comes an external pressure sensor and the temperature mode is internal.

Hello Mickey,

I was able to emulate it here on my end and it looks to be within the error target of 0.1% FSR. One thing that I noticed is different is that the Step 11: “Calibrate Nonlinearity (LinDAC)” was not checked. This function allows the user to calibrate nonlinearity versus stimulus.  The Auto-Cal Calibration Info looks fine. When calibrating each point, is the environment isolated in a temperature chamber to control the temperature at those temperature points? Are you seeing a target error of more than 0.1% FSR?

Best,

Errol

Hello Mickey,

Yes, the customer should check the box in step 11.  For the second question, what methods do they use for controlling temperature when calibrating the 3 temperature points?

Best,

Errol

Hi Errol,

When the customer checks the box in the step 11, the issue still exists. The issue is when the  temperature is below 0 degree C, the EEPROM data is 0000.

The calibration is fine when the  temperature is above 0 degree C.

The customer uses  the temperature control box to control. He put his board in  the temperature control box when he tests the  temperature.

There is the target error of more than 0.1% FSR. After the customer complete the calibration and the  calibration temperature range is from -40degree C to 125 degree C, then the output voltage is 0.55V~4.4V.

Hi Errol,
The customer has update the software. And he calibrates the temperature from-20 degree C to 25 degree C. The calibration process is fine. But there is still the issue when the customer write the data to EEPROM, only -20degree C is fine. Please see the attachment. 

Hello Mickey,

I have created a step by step PowerPoint to test the software.  I have also embedded a Pre-Cal file in the PowerPoint for the customer to load so we can try a sensor emulation to make sure everything is running properly software wise.  Have the customer follow the steps in the PowerPoint and send me the screenshots of the results.  Also could they send me a picture of their set-up with the external sensors attached to the EVM?

Best,

Errol 

PGA309 software calibration test with sensor emulation.pptx

Hi Errol,
Thank you very much.I will query the customer. Then I will send it to you.

Hi Errol,

The customer has the result for the test.  The external pressure sensor is a typical piezoresistive pressure sensor. The power supply for PGA309EVM is 5V and it is stable.

The connection diagram between the external pressure sensor and the PGA309EVM is in  the attachment. 

Please see the attachment. If you need the customer to provide more information, please tell me.

6332.PGA309 software calibration test.pptx

Hi Errol,

Update: When the customer change" temp ADC VRef 4.096V" into "internal temp ADC Ref 2.048V“, the error for the test result is less than 0.1%FSR.

But the result is different from the ”Table 2-9. Internal Temperature Mode Data —Register 0“ of the PGA309 User's Guide ( ).