LDC1314DIAL-EVM: Use EVM for custom LDC1314 HW?

Anthony,

I am closing this thread since we are already supporting this via email.

Regards,
John

Anthony,

Is it possible to provide the schematic and layout of the custom PCB and upload that info to this thread?

John

Thank you for the background email threads Anthony.

I had no idea of the history leading up to what the customer is seeing now.

Please confirm if my understanding is correct:

1. The customer is evaluating a prototype, the design of which was reviewed by our team.
2. The prototype is meant to measure between 0 degrees and 300 degrees.
3. The customer’s prototype is showing the glitching behavior with jumps between 180 and 290 degrees.
4. The customer is looking for any SW/HW background we can provide that will help speed up their troubleshooting.

One thing I didn’t see in the history is a mention of the angle to be measured in the customer's design (might have missed it).

Have they introduced a mechanical limit of 300deg, or is there a limit imposed by the LDC/sensor/target part of the design, or both? (or neither and its something else?)

 Best Regards,

John

Hi John,

I send some more background info by email.

The bottom line is:

-What could cause those glitches (issues with custom coil/targets design or TIDA-00508 GUI SW/MSP430 FW not adapted for custom target/coils tests)?

Thanks in advance,

A.

Anthony,

At this point, I do not know what the source of the glitches could be since we cannot reproduce and diagnose them on our end.
So I have some more questions:
Do the glitches happen at all dial settings, or just certain ones?
If it is just for particular dial settings, what are they?

John

John Miller - Sensing said:

At this point, I do not know what the source of the glitches could be since we cannot reproduce and diagnose them on our end.
So I have some more questions:
Do the glitches happen at all dial settings, or just certain ones?

Yes, They happen at all dial settings, although ich have changed different calibration from 0° to 360°.

I have save the glitches in the video.  I have change the angle from 60° to 310° with nearly 30° step. It seems the glitch is changed to 210° if the angle < 180°. At the angle 210° it seems stable. After 210° it changed to another direction.

See video sent offline.

Hi John,

The idea is if TI Team send me the Firmware for MSP430, so that we could change any parameters  or features in the Firmware to solve this gltches problem. 

regards,

 Qinghai 

Anthony,

Thank you for the update.
I have an EVM for the TIDA-00508 design and am installing the support GUI to see if there's anything that might help point to the cause of the glitches. 

Unfortunately our IT policies are preventing the GUI installation, so that won't happen until tomorrow. I will provide an update to this thread on Friday.

Regards,
John

Dr. Shi,

I will check our internal software database to see if it is available, and will update this thread on Friday.

Regards,
John

Anthony,
I tried some experiments with the dial EVM and the GUI and saw the GUI dial was jumping around until I squeezed the center of each side of the EVM between my thumb and forefinger. The GUI dial's jumping stopped and the GUI dial smoothly followed the EVM dial's setting. It behaved this way for any of the calibration modes. There must be some kind of poor connection causing the glitches. 

By the way, is the customer running a calibration of their PCB assembly? 

regards,
John

HI John,

I have used the different calibration for my PCB assembly. 

I have also used the original Target and Coil of the EVB. It was OK with original assembly without glichtes. 

Dr. Shi,

I checked with our management and their policy is that we do not provide the firmware as a standalone item because it is not subject to quality control separate from its function in the GUI.

Regards,
John

Hi John,

I have checked the connector like your suggestion. But It didn't solve the glithes problem.

Regards,

Qinghai 

Hi John, Hi Dr Shi,

Could it be on the Proto PCB side? May be the gap between coils and target changes when you turn the weel?
Are both PCB mechanical pushed together?
Can you provide a video showing the coils and target while you turn the weel?

A.

Hi,

The gap between coil and target is zero. That means, the target is placed directly on the coil (like in EVBoard). I have tried set the gap with 1 mm to 3 mm. It helps nothing for the glitches. 

I could not upload the figures here. I send you the figures and video per Mail.

Regards,

Qinghai 

Hi,

I have desoldered the four resonance capacitors. The glitches are disapeared. But the calibration are not working with 10° deviation. Is it dependend the resonance frequency of the firmare set up? Any ideas about this problem? shall I try to solder capacitors with above 100pF? 

regards

Qinghai 

Dr. Shi,

The TIDA-00508 EVM boards are calibrated when they are manufactured, so I think some form of calibration will be needed for your boards as well. I am not sure if or how to do this with our EVM and supporting software so I will look into it more and update this thread tomorrow.

Regards,
John

Dr. Shi,
I am sorry, but we do not have a reference design or library to offer for an LDC1314 angle calibration.
Calibration is usually part of our customers' "secret sauce" for their end products, so they develop their own algorithms tailored for their applications. 

Regards,
John