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Part Number: PGA305
Other Parts Discussed in Thread: USB2ANY
Is there a procedure available to calculate the coefficients for the compensation engine without access to an EVM or (by extension, the EVM in the GUI)? We've got a custom board which is functioning well with the raw data, but it's time to try to implement the temperature compensation and we appear to be stuck without having access to USB2ANY and the EVM... which we really aught not to need.
Hello David,
There is a separate DLL that is needed to generate the coefficients separately from the GUI. I have a DLL with some example code demonstrating how to use it. I need to track it down, and I will post tomorrow.
Regards,
Hello David,
Attached is the DLL and a csharp example of how to call its coefficient generation function:
https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/1023/PGAcoeffgen24.dll
#region Calibrate_Coefficients
case 100: // Do the Magic - Calibrate the coefficient values
double[] dac_k = new double[4];
double[] dac_n = new double[4];
double[] temp1 = new double[4];
double[] temp2 = new double[4];
// THE CODE BELOW WILL GENERATE k AND n LINEARITY COEFFICIENTS
// WHICH WILL BE LATER USED FOR DAC LINEARIZATION
// Note: This is only for DAC since the DAC might be non-linear when converting code into Voltage
// If the output data is read by a digital interface (For Example I2C) this is not needed
temp2[0] = Tools.StringBase16IntoDouble(Calib_P1DAC_box.Text) / 16384;
temp2[1] = Tools.StringBase16IntoDouble(Calib_P2DAC_box.Text) / 16384;
temp2[2] = Tools.StringBase16IntoDouble(Calib_P3DAC_box.Text) / 16384;
temp2[3] = Tools.StringBase16IntoDouble(Calib_P4DAC_box.Text) / 16384;
if (Calib_ModelSel_combo.Text != "4 Pressure, 4 Temperature") temp2[2] = (temp2[1] + temp2[3]) / 2;
//k1 and n1
temp1[0] = Tools.StringBase10_Into_Double(Calib_T1Vo1_box.Text) / Tools.StringBase10_Into_Double(Calib_VDDSupply_box.Text);
temp1[1] = Tools.StringBase10_Into_Double(Calib_T1Vo2_box.Text) / Tools.StringBase10_Into_Double(Calib_VDDSupply_box.Text);
temp1[2] = Tools.StringBase10_Into_Double(Calib_T1Vo3_box.Text) / Tools.StringBase10_Into_Double(Calib_VDDSupply_box.Text);
temp1[3] = Tools.StringBase10_Into_Double(Calib_T1Vo4_box.Text) / Tools.StringBase10_Into_Double(Calib_VDDSupply_box.Text);
if (Calib_ModelSel_combo.Text != "4 Pressure, 4 Temperature") temp1[2] = (temp1[1] + temp1[3]) / 2;
Calc_Slope_Intercept(temp1, temp2, ref dac_k[0], ref dac_n[0]);
//k2 and n2
temp1[0] = Tools.StringBase10_Into_Double(Calib_T2Vo1_box.Text) / Tools.StringBase10_Into_Double(Calib_VDDSupply_box.Text);
temp1[1] = Tools.StringBase10_Into_Double(Calib_T2Vo2_box.Text) / Tools.StringBase10_Into_Double(Calib_VDDSupply_box.Text);
temp1[2] = Tools.StringBase10_Into_Double(Calib_T2Vo3_box.Text) / Tools.StringBase10_Into_Double(Calib_VDDSupply_box.Text);
temp1[3] = Tools.StringBase10_Into_Double(Calib_T2Vo4_box.Text) / Tools.StringBase10_Into_Double(Calib_VDDSupply_box.Text);
if (Calib_ModelSel_combo.Text != "4 Pressure, 4 Temperature") temp1[2] = (temp1[1] + temp1[3]) / 2;
Calc_Slope_Intercept(temp1, temp2, ref dac_k[1], ref dac_n[1]);
//k3 and n3
temp1[0] = Tools.StringBase10_Into_Double(Calib_T3Vo1_box.Text) / Tools.StringBase10_Into_Double(Calib_VDDSupply_box.Text);
temp1[1] = Tools.StringBase10_Into_Double(Calib_T3Vo2_box.Text) / Tools.StringBase10_Into_Double(Calib_VDDSupply_box.Text);
temp1[2] = Tools.StringBase10_Into_Double(Calib_T3Vo3_box.Text) / Tools.StringBase10_Into_Double(Calib_VDDSupply_box.Text);
temp1[3] = Tools.StringBase10_Into_Double(Calib_T3Vo4_box.Text) / Tools.StringBase10_Into_Double(Calib_VDDSupply_box.Text);
if (Calib_ModelSel_combo.Text != "4 Pressure, 4 Temperature") temp1[2] = (temp1[1] + temp1[3]) / 2;
Calc_Slope_Intercept(temp1, temp2, ref dac_k[2], ref dac_n[2]);
//k4 and n4
temp1[0] = Tools.StringBase10_Into_Double(Calib_T4Vo1_box.Text) / Tools.StringBase10_Into_Double(Calib_VDDSupply_box.Text);
temp1[1] = Tools.StringBase10_Into_Double(Calib_T4Vo2_box.Text) / Tools.StringBase10_Into_Double(Calib_VDDSupply_box.Text);
temp1[2] = Tools.StringBase10_Into_Double(Calib_T4Vo3_box.Text) / Tools.StringBase10_Into_Double(Calib_VDDSupply_box.Text);
temp1[3] = Tools.StringBase10_Into_Double(Calib_T4Vo4_box.Text) / Tools.StringBase10_Into_Double(Calib_VDDSupply_box.Text);
if (Calib_ModelSel_combo.Text != "4 Pressure, 4 Temperature") temp1[2] = (temp1[1] + temp1[3]) / 2;
Calc_Slope_Intercept(temp1, temp2, ref dac_k[3], ref dac_n[3]);
// THE CODE BELOW WILL MAP THE DAC NON-LINEARITY TO THE
// LINEAR DESIRED OUTPUT
//Generate Desired DAC LSBs
temp2[0] = Tools.StringBase10_Into_Double(Calib_P1Vo_box.Text) / 5 * 16384; // 5V assumed VDD, 16384 because the DAC is 14 bits (2^14 = 16384)
temp2[1] = Tools.StringBase10_Into_Double(Calib_P2Vo_box.Text) / 5 * 16384; // 5V assumed VDD
temp2[2] = Tools.StringBase10_Into_Double(Calib_P3Vo_box.Text) / 5 * 16384; // 5V assumed VDD
temp2[3] = Tools.StringBase10_Into_Double(Calib_P4Vo_box.Text) / 5 * 16384; // 5V assumed VDD
//
// Populate DAC Linearization Matrix
double[] DACs_fixed = new double[16];
DACs_fixed[0] = dac_k[0] * temp2[0] + dac_n[0];
DACs_fixed[4] = dac_k[0] * temp2[1] + dac_n[0];
DACs_fixed[8] = dac_k[0] * temp2[2] + dac_n[0];
DACs_fixed[12] = dac_k[0] * temp2[3] + dac_n[0];
DACs_fixed[1] = dac_k[1] * temp2[0] + dac_n[1];
DACs_fixed[5] = dac_k[1] * temp2[1] + dac_n[1];
DACs_fixed[9] = dac_k[1] * temp2[2] + dac_n[1];
DACs_fixed[13] = dac_k[1] * temp2[3] + dac_n[1];
DACs_fixed[2] = dac_k[2] * temp2[0] + dac_n[2];
DACs_fixed[6] = dac_k[2] * temp2[1] + dac_n[2];
DACs_fixed[10] = dac_k[2] * temp2[2] + dac_n[2];
DACs_fixed[14] = dac_k[2] * temp2[3] + dac_n[2];
DACs_fixed[3] = dac_k[3] * temp2[0] + dac_n[3];
DACs_fixed[7] = dac_k[3] * temp2[1] + dac_n[3];
DACs_fixed[11] = dac_k[3] * temp2[2] + dac_n[3];
DACs_fixed[15] = dac_k[3] * temp2[3] + dac_n[3];
//Populate P ADC Linearization Matrix
double[] PADCs = new double[16];
PADCs[0] = Tools.StringBase16IntoDouble(Calib_P1T1_ADC_box.Text);
PADCs[4] = Tools.StringBase16IntoDouble(Calib_P2T1_ADC_box.Text);
PADCs[8] = Tools.StringBase16IntoDouble(Calib_P3T1_ADC_box.Text);
PADCs[12] = Tools.StringBase16IntoDouble(Calib_P4T1_ADC_box.Text);
PADCs[1] = Tools.StringBase16IntoDouble(Calib_P1T2_ADC_box.Text);
PADCs[5] = Tools.StringBase16IntoDouble(Calib_P2T2_ADC_box.Text);
PADCs[9] = Tools.StringBase16IntoDouble(Calib_P3T2_ADC_box.Text);
PADCs[13] = Tools.StringBase16IntoDouble(Calib_P4T2_ADC_box.Text);
PADCs[2] = Tools.StringBase16IntoDouble(Calib_P1T3_ADC_box.Text);
PADCs[6] = Tools.StringBase16IntoDouble(Calib_P2T3_ADC_box.Text);
PADCs[10] = Tools.StringBase16IntoDouble(Calib_P3T3_ADC_box.Text);
PADCs[14] = Tools.StringBase16IntoDouble(Calib_P4T3_ADC_box.Text);
PADCs[3] = Tools.StringBase16IntoDouble(Calib_P1T4_ADC_box.Text);
PADCs[7] = Tools.StringBase16IntoDouble(Calib_P2T4_ADC_box.Text);
PADCs[11] = Tools.StringBase16IntoDouble(Calib_P3T4_ADC_box.Text);
PADCs[15] = Tools.StringBase16IntoDouble(Calib_P4T4_ADC_box.Text);
//Populate T ADC Linearization Matrix
double[] TADCs = new double[16];
TADCs[0] = Tools.StringBase16IntoDouble(Calib_T1_TADC_box.Text);
TADCs[4] = Tools.StringBase16IntoDouble(Calib_T1_TADC_box.Text);
TADCs[8] = Tools.StringBase16IntoDouble(Calib_T1_TADC_box.Text);
TADCs[12] = Tools.StringBase16IntoDouble(Calib_T1_TADC_box.Text);
TADCs[1] = Tools.StringBase16IntoDouble(Calib_T2_TADC_box.Text);
TADCs[5] = Tools.StringBase16IntoDouble(Calib_T2_TADC_box.Text);
TADCs[9] = Tools.StringBase16IntoDouble(Calib_T2_TADC_box.Text);
TADCs[13] = Tools.StringBase16IntoDouble(Calib_T2_TADC_box.Text);
TADCs[2] = Tools.StringBase16IntoDouble(Calib_T3_TADC_box.Text);
TADCs[6] = Tools.StringBase16IntoDouble(Calib_T3_TADC_box.Text);
TADCs[10] = Tools.StringBase16IntoDouble(Calib_T3_TADC_box.Text);
TADCs[14] = Tools.StringBase16IntoDouble(Calib_T3_TADC_box.Text);
TADCs[3] = Tools.StringBase16IntoDouble(Calib_T4_TADC_box.Text);
TADCs[7] = Tools.StringBase16IntoDouble(Calib_T4_TADC_box.Text);
TADCs[11] = Tools.StringBase16IntoDouble(Calib_T4_TADC_box.Text);
TADCs[15] = Tools.StringBase16IntoDouble(Calib_T4_TADC_box.Text);
for (int i = 0; i < 16; i++) //Take care of 2's Complement
{
if (PADCs[i] > 32767) PADCs[i] = PADCs[i] - 65536; //Here the Data is 16bits from the ADC
if (TADCs[i] > 32767) TADCs[i] = TADCs[i] - 65536; // hence the values 65536 (Full ADC Span) and 32767 (Max Positive value)
}
//Now Calibrate the coefficients and digital gain/offset by using the external dll function
double[] Coefficients_norm = new double[16];
double[] Coefficients_off = new double[16];
int[] Coeff_array_size = new int[2];
double Temp_offset_norm = 0;
double Temp_offset_off = 0;
double Temp_gain_norm = 0;
double Temp_gain_off = 0;
double Press_offset_norm = 0;
double Press_offset_off = 0;
double Press_gain_norm = 0;
double Press_gain_off = 0;
double Fit_Error_norm = 0;
double Fit_Error_off = 0;
// INPUT PARAMETERS INTO Calibration_Coeff_Gen function
// CalPoint: 0 - 3P1T Calibration
// 1 - 3P3T Calibration
// 2 - 4P4T Calibration
// Off_Enable: 0 - Normal Version i.e. Fixed_ADC = GAIN * ADC + OFFSET
// 1 - Offset Version i.e. Fixed_ADC = GAIN * (ADC + OFFSET)
// NormScaleBits: Number of bits to Normalize (For PGA300, PGA302 and PGA304 it is always 14 bits)
// (For PGA305 it is always 22 bits)
if (Calib_ModelSel_combo.Text == "4 Pressure, 4 Temperature")
{
Calibration_Coeff_Gen(2, 0, 14, PADCs, TADCs, DACs_fixed, Coefficients_norm, Coeff_array_size, ref Temp_offset_norm, ref Temp_gain_norm, ref Press_offset_norm, ref Press_gain_norm, ref Fit_Error_norm);
Calibration_Coeff_Gen(2, 1, 14, PADCs, TADCs, DACs_fixed, Coefficients_off, Coeff_array_size, ref Temp_offset_off, ref Temp_gain_off, ref Press_offset_off, ref Press_gain_off, ref Fit_Error_off);
}
else if (Calib_ModelSel_combo.Text == "3 Pressure, 3 Temperature")
{
Calibration_Coeff_Gen(1, 0, 14, PADCs, TADCs, DACs_fixed, Coefficients_norm, Coeff_array_size, ref Temp_offset_norm, ref Temp_gain_norm, ref Press_offset_norm, ref Press_gain_norm, ref Fit_Error_norm);
Calibration_Coeff_Gen(1, 1, 14, PADCs, TADCs, DACs_fixed, Coefficients_off, Coeff_array_size, ref Temp_offset_off, ref Temp_gain_off, ref Press_offset_off, ref Press_gain_off, ref Fit_Error_off);
}
else if (Calib_ModelSel_combo.Text == "3 Pressure, 1 Temperature")
{
Calibration_Coeff_Gen(0, 0, 14, PADCs, TADCs, DACs_fixed, Coefficients_norm, Coeff_array_size, ref Temp_offset_norm, ref Temp_gain_norm, ref Press_offset_norm, ref Press_gain_norm, ref Fit_Error_norm);
Calibration_Coeff_Gen(0, 1, 14, PADCs, TADCs, DACs_fixed, Coefficients_off, Coeff_array_size, ref Temp_offset_off, ref Temp_gain_off, ref Press_offset_off, ref Press_gain_off, ref Fit_Error_off);
}
if (Fit_Error_norm == 1 && Fit_Error_off == 1)
{
Calib_Status_box.Text = "Error: Calibration Completed with unsuccessful results.\r\nInfo: Please Check your system settings and configuration and try again.\r\nInfo: If the issue persists please contact Texas Instruments Support.\r\n";
Calib_CANCEL_button.PerformClick();
break;
}
// The code below will decide which Version (Normal or Offset) has calculated a lower Simulated Error
// and will propose those calibration values.
if (Fit_Error_norm < Fit_Error_off) // Normal Version Wins
{
for (int i = 0; i < 16; i++)
Calib_Coefficients_final[i] = (int)(Coefficients_norm[i] * 16384); //16384 because NormScaleBits = 14
Calib_Temp_offset_final = (int)Temp_offset_norm;
Calib_Temp_gain_final = (int)Temp_gain_norm;
Calib_Press_offset_final = (int)Press_offset_norm;
Calib_Press_gain_final = (int)Press_gain_norm;
Calib_Norm_notOff = true;
Calib_Status_box.Text = "Info: Calibration Completed. Normal mode Algorithm used for lowest error.\r\n";
Calib_Status_box.Text += "Info: Simulated Fit Error Value = " + Fit_Error_norm.ToString() + "\r\n";
}
else // Offset Version Wins
{
for (int i = 0; i < 16; i++)
Calib_Coefficients_final[i] = (int)(Coefficients_off[i] * 16384); //16384 because NormScaleBits = 14
Calib_Temp_offset_final = (int)Temp_offset_off;
Calib_Temp_gain_final = (int)Temp_gain_off;
Calib_Press_offset_final = (int)Press_offset_off;
Calib_Press_gain_final = (int)Press_gain_off;
Calib_Norm_notOff = false;
Calib_Status_box.Text = "Info: Calibration Completed. Offset mode Algorithm used for lowest error.\r\n";
Calib_Status_box.Text += "Info: Simulated Fit Error Value = " + Fit_Error_off.ToString() + "\r\n";
}
Calib_Status_box.Text += "\r\n";
Calib_Status_box.Text += "Info: Best Fit Calibrated Coefficients Results:\r\n";
Calib_Status_box.Text += "H0 = " + Calib_Coefficients_final[0].ToString() + "\r\n";
Calib_Status_box.Text += "H1 = " + Calib_Coefficients_final[1].ToString() + "\r\n";
Calib_Status_box.Text += "H2 = " + Calib_Coefficients_final[2].ToString() + "\r\n";
Calib_Status_box.Text += "H3 = " + Calib_Coefficients_final[3].ToString() + "\r\n";
Calib_Status_box.Text += "G0 = " + Calib_Coefficients_final[4].ToString() + "\r\n";
Calib_Status_box.Text += "G1 = " + Calib_Coefficients_final[5].ToString() + "\r\n";
Calib_Status_box.Text += "G2 = " + Calib_Coefficients_final[6].ToString() + "\r\n";
Calib_Status_box.Text += "G3 = " + Calib_Coefficients_final[7].ToString() + "\r\n";
Calib_Status_box.Text += "N0 = " + Calib_Coefficients_final[8].ToString() + "\r\n";
Calib_Status_box.Text += "N1 = " + Calib_Coefficients_final[9].ToString() + "\r\n";
Calib_Status_box.Text += "N2 = " + Calib_Coefficients_final[10].ToString() + "\r\n";
Calib_Status_box.Text += "N3 = " + Calib_Coefficients_final[11].ToString() + "\r\n";
Calib_Status_box.Text += "M0 = " + Calib_Coefficients_final[12].ToString() + "\r\n";
Calib_Status_box.Text += "M1 = " + Calib_Coefficients_final[13].ToString() + "\r\n";
Calib_Status_box.Text += "M2 = " + Calib_Coefficients_final[14].ToString() + "\r\n";
Calib_Status_box.Text += "M3 = " + Calib_Coefficients_final[15].ToString() + "\r\n";
Calib_Status_box.Text += "\r\n";
Calib_Status_box.Text += "Info: Best Fit Gain and Offset Results:\r\n";
Calib_Status_box.Text += "Pressure (PADC) Gain = " + Calib_Press_gain_final.ToString() + "\r\n";
Calib_Status_box.Text += "Pressure (PADC) Offset = " + Calib_Press_offset_final.ToString() + "\r\n";
Calib_Status_box.Text += "Temperature (TADC) Gain = " + Calib_Temp_gain_final.ToString() + "\r\n";
Calib_Status_box.Text += "Temperature (TADC) Offset = " + Calib_Temp_offset_final.ToString() + "\r\n";
Calib_Status_box.Text += "\r\n";
Calib_Status_box.Text += "\r\n";
Calib_Status_box.Text += "To Program the Calculated Parameters to EEPROM click PROGRAM, otherwise click CANCEL.\r\n";
Calib_START_NEXT_button.Text = "PROGRAM";
calib_state_indx = 200;
// Note: Keep in mind that even after this code has completed the Calibration Coefficients are still in the Decimal format.
// The following case 200 (case "PROGRAM") which is not shown here will convert the decimal values into 2's complement HEX values.
// For PGA300, PGA302 and PGA304 these are 16 bits including the sign bit, for PGA305 these are 24 bits including the sign bit.
break;
#endregion
Note this is for generating 24bit coefficients.
Regards,
