Dynamic ramp saturation issue towards zero

[LEGR]

I am implementing a DRamp functionality with RTCESL version 4.62, where I have issues with the saturation when the absolute ramp value is falling.

LEGR_0-1755767839388.png

According to the documentation, the stop flag causes the ramp value to turn back towards the given instance, but this does not work in the implementation I did.

I tried both. A ramp with positive request and a ramp with negative request.

LEGR_1-1755767959990.png

LEGR_2-1755767966578.png
Is there a known issue or any other reason, the ramp does not respect the stop flag?

[Harry_Zhang]

Hi @LEGR 

May i ask which chip you are using?

BR

Harry

[LEGR]

Hi @Harry_Zhang,

we are running with LPC5534JBD100.

Best regards
Lennart

[Harry_Zhang]

Hi @LEGR 

I tried RTCESL 4.8.1 for CM33F and have not found the issue you mentioned. Please try use latest RTCESL library.

Could you send me the code so I can help you analysis.

BR

Harry

[LEGR]

Hi @Harry_Zhang ,

unfortunately, I can only find the version 4.7.1 for CM33F.

Real Time Control Embedded Software Motor Control and Power Conversion Libraries | NXP Semiconductor...

Where can I find the version 4.8.1?
Right now, we are using 4.6.3 and for 4.7.1 the only change is recompiling the KEIL libraries with a new compiler.

I attached the code I used for testing the function.

Best regards
Lennart

[Harry_Zhang]

Hi @LEGR 

May i ask what compiler you are using?

BR

Harry

[LEGR]

Hi @Harry_Zhang ,

I am wondering that you need the information, when you can recreate the issue. I already spent quite some time, that you really take a look at the described behavior.

The compiler I am using is:
arm-none-eabi-gcc (GNU Arm Embedded Toolchain 10.3-2021.07) 10.3.1 20210621 (release)

BR

Lennart

[Harry_Zhang]

Hi @LEGR 

Is it enough for you to fix only GFLIB_DRamp_FLT and rebuild library or also GFLIB_DRamp_F16, GFLIB_DRamp_F32 functions are used in your application?

In case all 3 DRamps need to be fixed We would estimate to send rebuild lib in next week.

BR

Harry

[LEGR]

Hi @Harry_Zhang ,

we are only running the GFLIB_DRamp_F16 and GFLIB_DRamp_F32, since our software still bases on an older controller, where no floating-point unit was supported.

BR

Lennart

[Harry_Zhang]

Hi @LEGR 

We have reproduced this issue and fix it.

The next release will wait for some time.

So we want to recompile the library for you.

BR

Harry

[Harry_Zhang]

Hi @LEGR 

The latest RTCESL will not be published alone on NXP website.

You can clone it from GIThub (nxp-mcuxpresso/rtcesl: NXP Real Time Control Embedded Software Library)

BR

Harry

[LEGR]

Hi @Harry_Zhang ,

I tried the ramp using RTCESL 4.8.1 for CM33F, but the result is the same.

Ramp_RTCESL4_8_1.png

The saturation only works while the absolute ramp value increases.

BR
Lennart

[Harry_Zhang]

Hi @LEGR 

We can reproduce this issue.

We are currently investigating this issue internally, and if there is any progress, I will inform you promptly. Thank you for your information.

BR

Harry