PGA309: How to use this as Exactly as PGA308

HI Sri,

In addition to temperature compensation, there are differences in features and performance between the PGA309 when compared with the PGA308.

The PGA309 uses an external EEPROM to store the calibration values, while the PGA308 uses OTP banks of memory.  The PGA309 offers sensor linearization, while the PGA308 does not offer this feature. The amplifier follows a similar architecture, but there are differences in the Front-End Gain settings as well as the output amplifier gains, and differences in the internal resistor values that set some of these gains. There are also differences in the coarse and fine adjusts ranges and also differences in the performance specifications.  Essentially, you could attempt to use gain settings that are present in both, but the devices are not identical. You could program the PGA309 to use the internal temperature sensor, and use external bridge excitation (if you don't wish to use the linearization function of the PGA309), however, the PGA309 will require the external EEPROM.  The PGA309/PGA308 EVM software have some similarities, but there are differences between them. 

In summary, you could choose settings in gain so the PGA309 will behave similar to the PGA308, and although the devices have similarities in the architecture; the settings, features, internal circuitry and performance is not identical.

Regarding the issue with the pre-cal, when I installed this software on a PC with Windows 10, although I have administrator privileges, and installed the software properly, I ran into an issue when trying to modify the Pre-Cal file, and sensor files used by the PGA309 GUI.  In order to resolve the issue, I had to manually change the permissions on the folders.  The following directories may need to add full control to the user:

:\Program Files (x86)\proj_PGA309EVM-USB\Model_Files
:\Program Files (x86)\proj_PGA309EVM-USB\Pre_Cal_Files
:\Program Files (x86)\proj_PGA309EVM-USB\Sensor_Emulator_Files.

Please see example below, let me know if you still have issue writing/saving the files.

Thank you and Best Regards,

Many Thanks,

Kind Regards,

Luis 

In order to allow the user full control, please perform the following steps:

1) Using Windows explorer, Browse to the folder,

Root directoy:\Program Files (x86)\proj_PGA309EVM-USB\Pre_Cal_Files

- Right click on the folder on explorer, select properties

2) Grant full-control to the user as shown below:

- Select Security, select your user name on the PC, and check mark "allow".

- Click on "Apply" and click on "OK"

Thanks for your fast response.

So If I wanted to not do the temperature compensation using PGA309 it can be possible with using EEPROM? And I'm not able to do figure out using this PGA309 EVAL board.

And I was able to change the permissions now I can create the new Precal and Model files but I was not able to load the new one that created. It's not changing to the one that created. 

Hi Sri,

The PGA309 has similar features/architecture as the PGA308; however, it is not the same device as the PGA308.  There are differences in the internal resistors to set the gain, some differences on the Zero DAC and Gain DAC adjustment ranges, and other differences in the device.   It is not the same device and there are differences on the specifications, so the PGA309 can programmed to behave similar but not exactly as the PGA308. 

The PGA309 external EEPROM stores temperature coefficients for the Zero DAC and Gain DAC adjustments with measured temperature and the PGA309 lookup logic contains a linear interpolation algorithm for DAC adjustments between stored temperature indexes. The device perform piecewise linear temperature compensation for the temperature indexes and associated temperature coefficients.  

During normal operation, on stand-alone mode,  after power-up, the device will read the EEPROM contents and verify the proper Flag and verify the checksum1 register value, perform a temperature measurement, and after this proceed into reading the Lookup tables, verify checksum2 and then apply the corresponding Gain/Zero DAC settings for the associated temperature reading.

The PGA309EVM software by default supports three different temperature readings; however, it allows you to program a single temperature reading on the calibration, avoiding the temperature compensation.

After changing the permissions on the folders, I am able to modify/create new pre-cal files using the EVM GUI.

Thank you and Regards,

Luis