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MiNe_85951
Level 7
Level 7
Distributor - TED (Japan)
50 likes received 500 replies posted 50 solutions authored

Dear Sirs and Madams,

 

We are evaluating the proximity sensor of PSoC4S MAX.

I have an additional question regarding the thread below that I consulted.

 

https://community.infineon.com/t5/PSoC-4/PSoC4S-MAX-How-to-allow-proximity-sensor-to-strong-ground/m...

 

(1)

Regarding the CIC2 filter, when I set the parameters using the information you provided and started the Tuner, the raw data was not displayed correctly.

MiNe_85951_0-1696554619236.png

After adjusting the parameters and reducing the number of samples to 2, the raw data is now displayed as shown in the image below.

MiNe_85951_1-1696554678152.png

(2)

Assuming that the evaluation environment has a strong ground plane nearby, we connected copper foil tape to GND as shown below.

MiNe_85951_2-1696554936617.png

When we conducted an evaluation by disabling the CIC2 filter and setting other parameters to those suggested by Infineon, we obtained the following results.

frequency

divider

48

64

Use SmartSense

Parameter

MiNe_85951_3-1696555139809.png

 

MiNe_85951_4-1696555139811.png

 

MiNe_85951_5-1696555139813.png

 

Waveform

MiNe_85951_6-1696555139814.png

 

MiNe_85951_7-1696555139814.png

 

MiNe_85951_8-1696555139815.png

 

SN

SN=0.23(S:14 N:64)

SN=0.05(S:5 N:110) 

SN=4.88(S:98 N:20)

 

SNR is when the distance between the sensor and the conductor is 15cm.

The evaluation results showed that using the frequency divider parameters recommended by you resulted in a dull waveform and an inability to secure S/N.

We would like to secure a detection distance of 15cm and a sufficient SNR, and would appreciate any feedback regarding this evaluation result.

 

Am I correct in my understanding that it is difficult to achieve this even with CapSense GEN5 in PSoC4S MAX if there is a strong ground plane near the sensor?

 

Regards,

6 Replies
PandaS
Moderator
Moderator
Moderator
100 solutions authored 5 likes given 250 sign-ins

Hi @MiNe_85951,

Thankyou for reaching out to us on this topic. I went through the previous thread. The tuning parameters are for the 4S Max device alone. Addition of the metal sheet(ground) will not go with the earlier parameters. The metal sheet will increase the parasitic capacitance of the system and thus we can see the charging discharging is not happening properly(need to drop the sense clock frequency even further).

Let me create the same scenario and replicate the issue, meanwhile could you please let me know if there is a insulator layer present in between the the metal sheet and ground.

Thanks and regards,

Sobhit

MiNe_85951
Level 7
Level 7
Distributor - TED (Japan)
50 likes received 500 replies posted 50 solutions authored

Hi Sobhit,

 

Thank you for your reply.

Does your reply mean the settings("The tuning parameters are for the 4S Max device alone") when only the PSoC4S MAX board is connected and no sensor board is connected?

Or do you mean if you use the PSoC4S MAX board and the  sensor board, but don't use a strong ground plane?

 

Since copper foil tape is used, there is a thin insulation layer on the seal area.

However, it is a strong ground plane because the copper foil surface is grounded.

 

I thought your company would have countermeasures even in such a harsh environment, however Is it correct to conclude that it is difficult to achieve both high-speed response (scan time < 5ms) and sufficient SNR (>15 at detection distance 10cm) in this environment?

 

Regards,

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MiNe_85951
Level 7
Level 7
Distributor - TED (Japan)
50 likes received 500 replies posted 50 solutions authored

As a result of evaluation in an environment where there is a ground directly under the proximity sensor, the SNR is lower when an active shield is installed than when an active shield is not used.

If it is difficult to increase the size of the guard sensor because the area of the casing (connected to the FG) is larger than the size of the proximity sensor (and active shield), is it correct to understand that there is no solution?

 

Regards,

0 Likes
JamieChaim
Level 1
Level 1
First like received First reply posted Welcome!

@MiNe_85951 wrote:

Dear Sirs and Madams,

We are evaluating the proximity sensor of PSoC4S MAX.

I have an additional question regarding the thread below that I consulted. 
boating test https://community.infineon.com/t5/PSoC-4/PSoC4S-MAX-How-to-allow-proximity-sensor-to-strong-ground/m...

Regarding the CIC2 filter, when I set the parameters using the information you provided and started the Tuner, the raw data was not displayed correctly.

After adjusting the parameters and reducing the number of samples to 2, the raw data is now displayed as shown in the image below.

Assuming that the evaluation environment has a strong ground plane nearby, we connected copper foil tape to GND as shown below.

When we conducted an evaluation by disabling the CIC2 filter and setting other parameters to those suggested by Infineon, we obtained the following results.

SNR is when the distance between the sensor and the conductor is 15cm.

The evaluation results showed that using the frequency divider parameters recommended by you resulted in a dull waveform and an inability to secure S/N.

We would like to secure a detection distance of 15cm and a sufficient SNR, and would appreciate any feedback regarding this evaluation result.

Am I correct in my understanding that it is difficult to achieve this even with CapSense GEN5 in PSoC4S MAX if there is a strong ground plane near the sensor?

Regards,


Meticulous adjustments to the CIC2 filter parameters as per the provided information and grounding the system with copper foil tape, I'm encountering challenges. Initially, the raw data wasn't displayed correctly, and only after multiple parameter tweaks and reducing the sample count to 2 did I manage to get a visible waveform. However, when disabling the CIC2 filter and following Infineon's recommendations for other parameters, the waveform became dull, and the signal-to-noise ratio (SNR) at a 15cm distance dropped significantly.

What they are saying is the recommended parameters are ONLY applicable when using the sensing expansion board by itself. Adding the ground plane significantly changes the characteristics of the touchpad, requiring the parameters to be changed. 

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MiNe_85951
Level 7
Level 7
Distributor - TED (Japan)
50 likes received 500 replies posted 50 solutions authored

If there is a strong ground plane near the proximity sensor, we cannot ensure sufficient SNR even if we change and tune various parameters.

I thought that your company could also use DVK to reproduce the environment, but I could not obtain a concrete solution.

Unfortunately, we have to decide that Infineon's capacitive proximity sensor cannot be used in such an environment.

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