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why pga309evm can not work after calibration with real sensor?

yao Tim
Intellectual 270 points
Other Parts Discussed in Thread: PGA309

1.why pga309evm can not work after calibration with real sensor?    i do  step by step according  guider.

2.when i check the test pin  indicate  pull down the test pin or pull up ? 

  • 0
    TI__Mastermind 27715 points

    Hello Yao,

    The TEST pin is pulled down in normal operation. This means that writing to the PGA309 registers does nothing, since the registers are always overwritten with the data from the external EEPROM. If the TEST pin is pulled up, then the internal state machine is disabled and you can write to the PGA309 registers directly to verify the signal path. The TEST pin is discussed in p. 70 of the PGA309 User's Guide.

    Unfortunately I've given you all the documentation available to help with calibrating the PGA309EVM with the emulator as well as with a real sensor. You should try posting a question on the Chinese TI forum at http://www.deyisupport.com/ for better results.

    Best regards,

    Ian Williams
    Linear Applications Engineer
    Precision Analog - Op Amps

  • 0 in reply to Ian Williams
    Intellectual 270 points

    hi.Williams

      why not use nonlin2.csv when calibrate a real sensor ?

  • 0 in reply to yao Tim
    TI__Mastermind 27715 points

    Hello Yao,

    The nonlin2.csv file is a sensor emulator file. This file defines the characteristics of a typical sensor in order to accurately emulate its output for calibration.

    When using a real sensor, you do not use the sensor emulator file since you are measuring the real sensor over pressure and temperature.

    Best regards,

    Ian Williams

  • 0 in reply to Ian Williams
    Intellectual 270 points

    hello.Williams

    could  you help me solve two problems?

    1.how to set up Temp Config  if i use RT-  act as external temperature  sense?

    how to set up block diagram below ?

    2.whether i need to put PGA309EVM board into  my  oven when  i use diode mode  to test temperature.

  • 0 in reply to yao Tim
    TI__Mastermind 27715 points

    Hi Yao,

    This is the proper configuration for RT- mode from the PGA309 User's Guide :

    Based on this configuration, you should use the following settings in the "Config Temp ADC" window:

    • Resolution without sign: 15b
    • Temp ADC External Reference Select: Vexc
    • Select Signal Source: External
    • Dif Input: TEMPin, GNDa
    • Internal Temp ADC Ref: Not checked
    • ADC Pre Gain: 8 V/V
    • Enable I_temp: Not checked
    • Continuous Conversion: Checked
    • Single Shot Conversion: Checked
    • Enable Turbo: Unchecked

    You do not have to put the PGA309EVM in the oven if you use the diode mode to test temperature. You can use the Sensor Emulator portion of the EVM to generate a voltage which corresponds to a diode voltage at a given temperature. 

    Click the "Run Sensor Emulator" button as shown on the software block diagram to open the sensor emulator window. Then, drag the temperature slider to generate a diode voltage over temperature.

    Best regards,

    Ian Williams

  • 0 in reply to Ian Williams
    Intellectual 270 points

    hi.Williams

    Maybe you not understand my second question   i asked last time.i mean if i use internal  diode to test  temperature when to calibrate my real bridge sensor .whether need to put the evm board into oven?

    i have  calibrated  my bridge sensor  use  Rt-  mode,but there are some problems;

    1.the Vout is not reach my set on target.this picture is my calibration

    Vout max is 4.5V and  Vout  min is 0.5V  on my setting ,but result is  Vout max just 4.2V ,Vout  min 0.055V.

    i am confused.do you know why?

    2.now i design one new PCB board which  contain  pga309 and   EEPROM. One PRG port  has been designed on my pcb board .I want to konw it is right or not that i connect my PCB board to PGA309  USB-DAQ-platform to calibrate my bridge sensor  by PRG port?(OR can i use pga309 evm  PRG port to program my  new design board which contain PRG port.)