EVM430-FR6043: EVM430-FR6043

Hi A-Jay,

Could you provide some more context for this issue so we can begin helping you?

What exactly is the set up for your EVM (what transducers, transducer positioning, pipe, etc.)?

Is this spike always occurring at a regular interval? Or is it random?

Thanks

Hi Dylan, 

I am using some 2 X 300Khz transducers to measure the air flow within a 21mm ID pipe, the transducers are positioned at 45Deg to the pipe and are in the wetted area so the ultrasonic signals only pass through air. 

the spikes are completely random, sometimes seconds between spikes sometimes minutes.

the spikes do not occur when there is no flow so the build is good, and when there is flow the values given in the waveform tab are within 5% of what i expect so this again shows the build is good. So i am unsure as to what is causing the issue.

Thanks 

A-Jay,

Could you also provide me with the transducer length, as well as the parameters (and advanced parameters) you are using?

Thank you

the transducers are spaced around 29.7mm apart, here is one of the config files that i have been using  

<?xml version="1.0" encoding="UTF-8"?>
<ussMspGui>
	<settings>
		<isLogging>true</isLogging>
		<logLocation>C:\Users\a-jay.gorman\USS_02_30_00_03\USSWorkspace\USS_Project</logLocation>
	</settings>
	<configParams>
		<target>gas</target>
		<board>EVM430-FR6043</board>
		<device>MSP430FR6043</device>
		<lph_gpm>lph</lph_gpm>
		<f1f2>280.0 410.0</f1f2>
		<patternSeq>2</patternSeq>
		<gapBetweenPulseAndCapture>110.0</gapBetweenPulseAndCapture>
		<numberOfPulses>8.0</numberOfPulses>
		<gapBetweenUpsAndDns>150.0</gapBetweenUpsAndDns>
		<gapBetweenDnsAndUps>500.0</gapBetweenDnsAndUps>
		<gainControl>20.5</gainControl>
		<areaConstant>77</areaConstant>
		<xt2Freq>8000</xt2Freq>
		<sigSamplingFreq>1000.0</sigSamplingFreq>
		<adcSamplePulse>80</adcSamplePulse>
		<deltaTOFOffset>0.0</deltaTOFOffset>
		<absTOFAdditionDelay>0.0</absTOFAdditionDelay>
		<captureDuration>150.0</captureDuration>
		<intrplCorrTableSize>0</intrplCorrTableSize>
	</configParams>
	<devModeParams>
		<param1>3</param1>
		<param2>100.0</param2>
		<param3>200000.0</param3>
		<param4>20000.0</param4>
		<param5>200000.0</param5>
		<param6>120.0</param6>
		<param7>10000.0</param7>
		<param8>384.0</param8>
		<param9>6.0</param9>
		<param10>0.0</param10>
	</devModeParams>
	<configCalibParams>
		<maximumVFR>10000.00</maximumVFR>
		<calculateTemp>0</calculateTemp>
		<minTempLUT>5</minTempLUT>
		<maxTempLUT>60</maxTempLUT>
		<tempResLUT>1.000</tempResLUT>
		<transducerLen>9.432</transducerLen>
		<calibType>0</calibType>
	</configCalibParams>
</ussMspGui>

This config file works perfectly well for my setup and gives accurate results so the major parameters do not need changing, I just need to know what could be causing this random spiking.

As i said, the meter works very well for a time so the config is clearly not the issue.

every time i hit request update the values go to their expected value (around 4000LPH, therefore the config is correct) but after a second they spike (12000-22000LPH), what is causing this?

A-Jay,

It is possible that your parameters are causing the intermittent spikes in you ToF calculations. Sending me images of your ADC captures and frequency sweep may also help identify the problem.

However, your UPS to DNS gap is quite small. This can lead to the device accidentally reading reflections of the UPS when it is trying to read the DNS. Assuming your absolute ToF is accurate at 150 us, it seems to me that the UPS could be bouncing back and arriving close the DNS, which will lead to problems. Perhaps try increasing this time to see if this helps. Otherwise, I will take a look at your ADC capture and frequency sweep to see if I can identify any problems there.

Hi Bryan, 

thank you for that advice I will give it a try and see if it helps with the problem.