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Dear Sirs,
My customer asked us about I°Dial&Evm of LDC1314.
1.Can 1 ° dial application's angle calculation / display program be operated using LDC 1314 EVM?
2.Can 1 ° dial application angle calculation / display program change parameters (register contents) in the program?
3.About 1 ° dial application calibration method, please tell me the concrete method of Shape Pre-Distortion.
4.About 1 ° dial application calibration method, please tell me the concrete method of Phase Skew Correction.
5.In order to have customers create programs, 1 ° application program source files are required.
Could you please give me a source file.
Best Regards,
Y.Hasebe
Hi Hasebe,
1. The 1° dial already comes with the LDC1314 and MSP430, which can be connected to the computer via usb to show the angle display.
2. The LDC1314 registers can be changed using the port commands. Refer to section 8.1 in the data sheet.
3. Shape Pre-distortion essentially makes data A and B closer to the cosine and sine functions in order to achieve more accurate measurements by using the following formulas:
A = sign(A) x abs(A)^EXP and B = sign(B) x abs(B)^EXP
where sign is the standard sign abs, is the absolute value, and EXP is the number that affects the shape of the waveform
4. Phase Skew Correction is the last step in data processing. This is required as after magnitude calibration, phase errors could still be there due to mechanical tolerance and surrounding metals. It is done by interpolating four known skew correction points from calibration, and using the following formula:
5. For the source file, I will have to look into it and get back to you later
Thanks,
Jiashow
Hi Hasebe-san,
Once you install the TIDA-00508 LDC1314 Inductive Dial GUI and Firmware Installer, you can find all the source files for the EVM in the "EVM Firmware" folder and GUI in the "PC GUI" folder.
The EVM uses MSP430, which can be programmed using Code Composer Studio.
Data processing and calibration are done in the GUI software. The firmware in the MCU reads data from LDC1314 and sends it to the GUI for processing. Specifically, the source code for Shape Pre-Distortion and Phase Skew Correction can be found in the PC GUI -> source -> Form_Main.vb
Best,
Jiashow
Hello Jiashow-san,
Thank your for your reply.
I found EVM firmware folder and PC GUI.
Also, I checked Form_Main.vb.
But I do not know where the Shape Pre-Distortion and Phase Skew Correction program is.
Please let me know it.
Best Regards,
Y.Hasebe
Hi Hasebe-san,
All the data processing (including shape pre-distortion and phase skew correction) occurs in the function "AB_to_Theta". I recommend following along the data processing procedures (pg 13-15) in the 1-degree dial datasheet to understand the code.
Best,
Jiashow
Hello Jiashow-san,
Thank you for your reply.
I found shape pre-distortion and phase skew correction in "Form_Main.vb".
Also checked data processing procedures in datasheet.
Best Regards,
Y.Hasebe
Hello Jiashow-san,
My customer asked us additional questions.
1.Please let me know that detailed procedure for changing the setting using the port command from the PC.
(For example, in the case of changing angle calculation)
2.Do you know how to rewrite resister values of 1 ° dial application angle calculations and display without program development means?
For example, the following method etc
・Control by GUI ⇒ I understand that this is impossible.
・Rewrite the contents of the setting file somewhere in the installation folder etc.⇒ I have recognized that it is same the above question.
3.About "EXP" of Shape Pre-distortion
I understand that the tendency of the output data is close to a sine wave.
Do you know how to determine the value of EXP?
4.About ENOB
Do you have the relational formula between output gain and ENOB?
5.GUI for 1°Dial
What does the slider at the bottom of the GUI mean?
Also, please let me know how to use.
6.About 1-Degree Dial Demo GUI
There was an Excel file named "Dial Calib.xlsx" in the "Config Files" folder of the installation folder.
We have recognized that the angle calculation method for each calibration method is described.
Sheet of "Dial Calib.xlsx" "DIAL - ATAN 4P"
→ Calculate angle at "4-point" in tidu 953
Sheet of "Dial Calib.xlsx" "DIAL - 1T"
→ Calculate angle with "1-turn" or "Dyamic" in tidu 953
Is this correct?
Best Regards,
Y.Hasebe
LDC_Dial_Calculator.xlsxHello Hasebe-san,
3) Attached is a calculator tool which can help determine the EXP value. You will need to collect output code data at multiple angles to determine the appropriate EXP value.
4) The ENOB is a function of the RCOUNT setting. Note that using the OUTPUT GAIN feature does increase the resolution, but also reduces the maximum signal amplitude. For most applications, the signal amplitude is much smaller than full scale range, and so this improves the SNR.
5) It repeats the dial as a linear output.
Regards.
ChrisO