MSP430FR6047: The signal strength is very low when used on metal pipes.

Hi Antony,

If I understand your description, your sensors on located on the 'outside' of the metal pipe?  If this is true, this won't work.  Metal will totally reflect the ultra-sound signal.  Plastic won't and that's why those materials work.

Hi Dennis, Thanks for your reply. Yes, It is a V-Mode Clamp on flowmeter, so is there any way we can avoid reflection, I have seen some clamp on flow meter working on metal pipes.

Hi Antony,

Let me revise my comment and say it's not impossible, just difficult with lower power levels.  There are some techniques to boost the drive voltage on the transducers so let me dig up some information on that.

Thank you so much. I found this thread very useful (+) EVM430-FR6047: Ultrasonic Design Center: Calibrating clamped-on transducers to work with metal pipe - MSP low-power microcontroller forum - MSP low-power microcontrollers - TI E2E support forums.

It is from 3 years ago, In the above thread the TI engineer mentioned they were working on a design to make MSP430-FR6043 for water meter application.  It has an external amplifier so it would be suitable for metal pipes, so did TI come up with a design? 
I have EVM430-FR6043 (PCB Rev C), if I modify the hardware and update software as mentioned in the thread would it work for the metal pipes?

Thanks
Antony

Hi Antony,

Exactly.  That is what I'm checking on.  It's still early in the morning here so our USS expert won't respond for a couple of hours, but I will get you what you need.

Hi Antony,

Ok, I checked with Eddie, who had responded in the link you provided regarding metal pipes, and he said no further development was done.  But as you probably already know, the EVM430-FR6043 has external circuits that allow you to boost the drive using 5V.  From what I'm being told, measuring gas is a bit more challenging and often requires higher drive strength.  Lucky for you, the external circuit can be used to drive your transducers for water flow at 5v, which should help penetrate the metal.  Refer to Eddies post for modifying the EVM430-FR6043 from gas to water.  There also instructions in the EVM430-FR6043 hardware users guide showing jumper configurations to use the on-board +5v.

That's about the best I can do for you at this point.  Give it try and let me know how it works.

Hi Dennis,

Thanks for all your help. Just couple of questions more

1. Which firmware I have to flash in EVM430-FR6043 for it to work as water meter? Is it MSP430FR6043EVM_USS_Gas_Demo_EVM_v2_0_AFE3v3_02_30_00_01 ?
2. In USSD center which meter option do I have to choose?
3. When I choose EVM430-FR6043 the excitation frequency is limited to 550 KHz.

Thanks

Hi Dennis, I have 't heard from you for a while. Please reply to my queries whenever possible.

Hi Antony,

Super sorry on the delayed response.  The EMV430-FR6043 can be used for water, but requires some modifications to the PCB.  Regarding the SW, you will have to use the SW written to support water.  I'll pulling together the details for you now.

Thank you so much for your response. I have done the PCB modifications. 

HI Dennis, Where can I find the EVM430-6043 SW written to support water?  Thanks.

Hi Antony,

The SW library and example code for the FR6047 is here.

Since you are doing this on the EVM430-6043, there might be a little porting.  I'm not familiar with what would be required, so let me find out.

Hi Antony,

I checked with Eddie and he says:

No need to modify the SW, in the water demo application below, there are projects for both 6047 and 6043.  It installs to the directory below.

C:\ti\msp\UltrasonicWaterFR604x_02_40_00_00_golden\examples\USS_Water_Demo\CCS

 https://www.ti.com/tool/download/USS-SWLIB-WATER

Hi Dennis, 

I have done the HW modifications and tried to flash the water demo application file load error occurred, to remove this error I changed the linker command file and it flashed successfully. 

However, in USSD when I try to connect EVM4306043 it says "HID Bridge Connected -- waiting for device". In the options to choose meter I tried  custom PCB, MSP430FR6043 water and EVM430FR6043 as well still no connection.

Below is my connections to EVM430FR6043.

Is there something I am doing wrong? Waiting for your valuable advise.

Thanks and regards
Antony

Hi Antony,

Can you try the pre-built water example for the FR6043 located in your installation directory:

Hi Dennis,

Thanks for that, I was able to flash the above pre-built water meter example. 

However, the signal strength is comparatively better but not good enough to measure DTOF in steel pipe. The signal strength remains same with and wothout additional 5V. I tried setting JP1 and JP2 for 5-V operation as explained in EVM430-FR6043 hardware guide (ti.com) but there is no change in the ADC signal.

ADC signal capture of EVM430Fr6043 on a steel pipe

Below pictures shows my HW and SW configuration.

Even though the gain is maximum the ADC is between 650 and 150. and every now and then I get error code 103 - "Time between measurements is greater than UPs0 to UPS1 Gap". 

Is there anything else I have to do to enable the additional 5V.

Thanks and regards
Antony

Hi Antony,

Can you confirm you are generating 5v pulses?  Measure with an oscilloscope.  If you are, that's the best that can be done with the EVM.  The USS team did not do any experiments with voltages higher than 5v.

Hi Dennis,

Here is what I got when measured with oscilloscope.

The Voltage is less than 3.5 V.

Do you think the ADC signal I obtained (refer previous message) is good enough to measure DToF?

Would be able let me know the drive voltage for MSP430FR6047.

Thanks and regards
Antony

Hi Antony,

Something is definitely not right here.  If you have a jumper between JP2 2-3 and jumpers on JP5 and JP6, you should be able to measure transmit pulse voltage where the transducers connect on the PCB, J5 and J6.  Where are taking your measurement?

Hi Dennis, 

Thanks for your response. According to this thread link the transducer are connected to J9 for water metering as shown in the picture in thread, I measured the transmit pulse voltage at J9, and in the same thread Eddie explains to remove jumper from JP4 and JP6. However I put the jumpers back on but pulse voltage remains same.

Thanks