MSP430FR5043: Best way to design external amplifier for USS flow meter

Christian Paetz

Part Number: MSP430FR5043
Other Parts Discussed in Thread: EVM430-FR6043

Tool/software:

Hi, I have designed a clamp-on flow meter for plastic pipes based on FR5043 that works according to expectations.To support stainless steel pipes I understand that an external amplifier is needed. This task creates some questions.

1. I do have an EVM430FR6043 reference board for gas metering. How can I use this for water metering ( 1 MHz transducers). Will the normal library support the switching signals to the analog frontend? Checking the schematics of the FR603 board I would conclude that the following signals are needed?

P1.1: Tx5VEn
P1.0: TXPwr
P2.2: RxPwr
P2.3: TxSel
P3.6: RxSel1
P3.7: RxSel2
P6.7: RxEn

Correct ?

2. There is another reference design called TIDA 01486 zjat is recommended together with the EVM6047. How to buy a TIDA board for testing (EVM6047 is available)?

3. Comparing the two reference designs ( TIDA01486 and FR6043), which one do you recommend?

Regards

Christian

6 months ago

0 Sal Ye 6 months ago

TI__Mastermind 25005 points

Hi Christian,

Let me ask the team expert on the USS design and feedback to you.

B.R.

Sal

0 Cash Hao11 6 months ago

TI__Mastermind 46765 points

Hi,

For hoe to use EVM430-FR6043 board for water metering. Please refer to this app note. https://www.ti.com/lit/ug/tidues5a/tidues5a.pdf

Best regards,

Cash Hao

0 Christian Paetz 6 months ago in reply to Cash Hao11

Prodigy 130 points

Hello Cahs, I do know the document you mentioned and would conclude that you recommend the FR403 reference above the TIDA. Got it! Can you please elaborate on using the I/Os in the lib. Not knowing the external amplifier I had used some of the I/Os for different functions. How to I enable the lib to control the outside amplifier? Is the list above for need control I/os correct ?

Its my understanding (2.3.1.1 of the document) that in water meter configuration the external amplifier is not used. However, I _do_ want to use the external amplifier ?!?

Chr.

0 Cash Hao11 6 months ago in reply to Christian Paetz

TI__Mastermind 46765 points

Hi,

You can try add __AFE_EXT_3v3__ in project->properties->build->MSP430 compiler->predefined symbol. But I have not tested with this setting before, not sure if this can work as you required.

Best regards,

Cash Hao

0 Christian Paetz 5 months ago in reply to Cash Hao11

Prodigy 130 points

seems that this refers to the external Power Source.

The answer to the question above was:

1) https://software-dl.ti.com/msp430/msp430_public_sw/mcu/msp430/USSSWLib/USSSWLibGas/02_30_00_03/exports/USSLib_02_30_00_03/docs/LibUsersGuide/markdown/CodeExamples.html?highlight=external%20afe describes which GPIO sare needed to control the externalAFE.

2) external AFE is enabled by USSSWLIB_ENABLE_EXTERNAL_CIRCUITRY_CONTROL : USS_Lib_HAL.h

This leaves one question from thelost above: Can buy complete TIDA 01486 boards ?

Chr.

0 Cash Hao11 5 months ago in reply to Christian Paetz

TI__Mastermind 46765 points

Hi,

Predefined the __AFE_EXT_3v3__ should let the compiler to build USSSWLIB_ENABLE_EXTERNAL_CIRCUITRY_CONTROL as enabled.

The TIDA 01486 is not for sell. Customer can download the layout file of this design and build the board for test by themselves.

Best regards,

Cash Hao

0 Christian Paetz 5 months ago in reply to Cash Hao11

Prodigy 130 points

Thank you for the support. We will design the AFE accordingly. One last point: schematicsGas2.jpg is optimized for gas metering using 200 KHz transducers. Any recommendations for the component changes for 1MHz water transducers (red markings)?

0 Cash Hao11 5 months ago in reply to Christian Paetz

TI__Mastermind 46765 points

Hi,

I can not see your figures due to the company firewall. But some thoughts from my side as below.

1. The gain setting R60/R61 may need change.

2. The low pass filter R63 and C44 may need change.

Best regards,

Cash Hao

0 Christian Paetz 5 months ago in reply to Cash Hao11

Prodigy 130 points

Yes, the low-pass R63/C44 seems easy. C44 = 200 pF => 1.44 MHz. The gain R63/R61 is easy too. I am uncertain about the C39 effect and even more about the network R44, R45, C35, R42, C36, which is commented as "for gas termination". Is there a need for water with 1 MHz ?

Chr.

0 Cash Hao11 5 months ago in reply to Christian Paetz

TI__Mastermind 46765 points

Hi,

I would say the C39 is used for suppressing high frequency noise. For water meter application, I think you can remove it.

For the network, R44, R45, C35, R42, C36, they are the same as R65, R67, C45,C43 and R66. If you change one of them, you also need to change the other one. But I think it is not necessary to change these values for water meter at this stage. You can keep them and test with your transducer first. Then try tunning the values to get a better receive signal.

Best regards,

Cash Hao

0 Christian Paetz 5 months ago in reply to Cash Hao11

Prodigy 130 points

Thank you very much! I will move ahead and see.

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MSP430FR5043: Best way to design external amplifier for USS flow meter