why ZERO dac and GAIN dac is too large of my pga309evm calibration

Hello Yao,

Could you please explain to me how you're calibrating the sensor? What connections are you using on the PGA309EVM and how are you generating the pressure and temperature signals?

Best regards,

Ian Williams
Linear Applications Engineer
Precision Analog - Op Amps

hello  Williams.

   thank  you!

    firstly  i connect one real sensor to TEST  board port:T1,T5,T4,using pga309 internal  ADC  sensor

    connections :        signal+_________T4:Vin1

                                     signal-_________T4:Vin2

                                      Vexc___________T1:Vsensor

                                      GND___________T1:GND

JMP  setting:          JMP4:ext

                                 JMP5:ext

                                 JMP12:Vexc

                                 JMP17:ext

and then put the board  into fridge or oven.

i set three calibrate  temperature point .10,25,45.and also have two  weight  load 250g   500g.

At first i put the board into fridge,hang  nothing   on sensor  when temperature reach  10 degree,then hang 500g weight load,and  next steps follow  the  powerpoint  you supply.Moving the board  into oven after  finished  temperature calibration at 10 degree, Not cut off the power supply when moving.

Voltage  target setting is  max 4.5V    MIN  0.5V

there is part of  my calibrations:

              Vout  max                 Vout  min                   GAIN  DAC

29           4.2875                      0.05544                     3.910

40           4.1980                      0.05544                     3.8749

45           4.1973                      0.05559                     3.8820

i  am confused.I think  GAIN  DAC is wrong,because it over scale

could you give me a right connections that use real sensor with internal TEMP sensor mode on  test board .

my sensor have  four  line: Vexc  GND, Signal+,Signal-.

Best regards

hi.Williams

please  teach  me  how to set software  and  hardware if i connect one Diode  to  TEMPin  PIN to test terperature.

and how to set  Config  Temp.

Hello  Williams,

  I  use  PGA309 EVM to calibrate my real sensor.the picture is below

i prepare   one fridge and one oven,also prepare weight for 200g,500g,50g;

using internal Temp  sensor of  PGA309;

the calibration steps is:

1.set three degree 10,25,45  ;and  then  put the board into fridge,hang nothing on sensor when temperature reach 10 degree.then click continue.  next hang  500g on sensor after finish last step.  the following steps according  the powerpoint you supply.   JMP setting that you have teached.   I am not cut off the power supply when moving  the board from fridge and putting the board into oven.

the calibration result is not right,for example   Voltage output in my Pre-Cal Max voltage  is  4.5

                                                                                                                                       min  voltage  is  0.5

                                                                                    but my calibrations is :  max  4.36    min 0.0554

especilly the value of  GAIN  DAC ,my GAIN  DAC value over the scale of right.right GAIN  DAC maybe 0.6.but my GAIN  DAC  is 3.8,