Texas Instruments MSP430FR6047 User manual

User’s Guide
Water Flow Meter
ABSTRACT
This getting started guide reviews the contents of the MSP430FR6047 ultrasonic sensing evaluation module and
tells you how to quickly get started with the MSP430FR6047 device for a water flow meter solution. The
information in this guide also applies to the MSP430FR600x and MSP430FR6043 ultrasonic sensing evaluation
module when used in the water metering configuration. For more information on the EVM430-FR6043 in water
metering configuration, see the Optimized ultrasonic sensing metrology reference design for water flow
measurement.
Table of Contents
1 Introduction.............................................................................................................................................................................2
1.1 Package Contents..............................................................................................................................................................2
1.2 What is Not Included.......................................................................................................................................................... 2
1.3 System Requirement..........................................................................................................................................................2
1.4 MSP430FR600x Evaluation............................................................................................................................................... 2
2 Connect the EVM to the Flow Meter......................................................................................................................................3
3 Flashing the EVM and Installing the GUI..............................................................................................................................4
4 USS GUI................................................................................................................................................................................... 5
4.1 Connecting to the Platform.................................................................................................................................................5
4.2 Configuration Parameters.................................................................................................................................................. 6
4.3 Capturing the ADC Signals...............................................................................................................................................11
4.4 Capturing Waveforms.......................................................................................................................................................14
4.5 Frequency Response....................................................................................................................................................... 15
5 Meter Characterization......................................................................................................................................................... 16
5.1 Single Shot Standard Deviation....................................................................................................................................... 16
5.2 Zero Flow Drift Testing..................................................................................................................................................... 16
5.3 Flow Testing..................................................................................................................................................................... 17
6 Revision History................................................................................................................................................................... 18
List of Figures
Figure 2-1. EVM430-FR6047 Connected to Flow Meter............................................................................................................. 3
Figure 2-2. EVM430-FR6047 Jumper Settings............................................................................................................................3
Figure 3-1. Select MSP430FR6047 Device.................................................................................................................................4
Figure 3-2. Load Image............................................................................................................................................................... 4
Figure 4-1. USS GUI Connected to EVM.................................................................................................................................... 5
Figure 4-2. Parameters Tab......................................................................................................................................................... 6
Figure 4-3. Configuration Timing Diagram...................................................................................................................................7
Figure 4-4. Advanced Parameters Tab........................................................................................................................................ 8
Figure 4-5. Representative Captured Waveform With Interpolation............................................................................................ 9
Figure 4-6. Captured ADC Signal.............................................................................................................................................. 11
Figure 4-7. Gap Between Pulse Start and ADC Capture Set Too Long.................................................................................... 12
Figure 4-8. Gap Between Pulse Start and ADC Capture Set Too Short....................................................................................12
Figure 4-9. Captured ADC Signal With No Water or Bad Connection....................................................................................... 13
Figure 4-10. Capturing Waveforms............................................................................................................................................14
Figure 4-11. Frequency Sweep Peak Amplitudes......................................................................................................................15
Figure 5-1. Single Shot Standard Deviation.............................................................................................................................. 16
Figure 5-2. Flow Test Setup.......................................................................................................................................................17
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All other trademarks are the property of their respective owners.
1 Introduction
Thank you for requesting the MSP430FR6047 sample kit. This getting started guide reviews the contents of your
kit and provides an overview on how to quickly get started with the MSP430FR6047 experimental device for
water flow meter solution.
1.1 Package Contents
The package includes:
1. USS evaluation module (EVM) version 2.0 hardware that has the MSP430FR6047 device with interfaces to a
transducer pair: http://www.ti.com/tool/EVM430-FR6047
2. The graphical user interface (GUI) to control the configurable parameters of the transducers and view the
results including the delta time of flight (dToF), absolute time of flight (aToF), measured flow rate, and ADC
waveforms: http://software-dl.ti.com/msp430/msp430_public_sw/mcu/msp430/USSSWLib/USSSWLibWater/
latest/index_FDS.html
3. An application example project that is supported by Code Composer Studio™ IDE (CCS) or IAR Embedded
Workbench® IDE. This project uses TI’s Ultrasonic Sensing Solution (USS) Library and interfaces to the GUI:
http://software-dl.ti.com/msp430/msp430_public_sw/mcu/msp430/USSSWLib/USSSWLibWater/latest/
index_FDS.html
4. The USS library and supporting documentation of the APIs that are available in the library: http://software-
dl.ti.com/msp430/msp430_public_sw/mcu/msp430/USSSWLib/USSSWLibWater/latest/index_FDS.html
1.2 What is Not Included
An Audiowell flow sensor with brass pipe is used as an example in this document. This sensor is available from
the Audiowell Electronics website.
1.3 System Requirement
The system requires the latest Java and Uniflash standalone flash tool. If not already installed, they are available
from https://java.com/en/download/ and http://www.ti.com/tool/UNIFLASH, respectively
1.4 MSP430FR600x Evaluation
The MSP430FR600x variant devices do not have EVM hardware available, but share the same pinout as
MSP430FR6047. To evaluate MSP430FR600x, the EVM430-FR6047 can be used. The U1 IC must be de-
soldered and replaced with the MSP430FR600x device. The water demo software discussed in Section 3
includes a build for the MSP430FR6007 device, which should be use in this configuration
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2 Connect the EVM to the Flow Meter
This section describes the hardware connections. For more details of hardware connections, see the EVM430-
FR6047 Hardware Guide.
1. Connect the EVM430-FR6047 to the flow meter (see Figure 2-1).
Figure 2-1. EVM430-FR6047 Connected to Flow Meter
2. Connect the jumpers as shown in Figure 2-2. The COMM_IRQ, COMM_SDA, and COMM_SCL jumpers on
the J5 header are required for communication with the GUI. TEST and RST jumpers on J2 are required to
program the board. The POW_SEL switch should be in the middle position(ezFET), J1 in the right position,
and both J3 jumpers set to use USB power. The jumper locations are highlighted in Figure 2-2.
Figure 2-2. EVM430-FR6047 Jumper Settings
3. Make sure that there is water in the flow meter.
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4. Connect a USB cable from the PC to the EVM and verify that LED D201 (power good) is illuminated and LED
D202(HID enumeration) blinks on the EVM.
Note
If LED3 is lit, this indicates an error. Connecting to the GUI will show the error in the errors tab. If
the error is "No signal detected in up and downstream channel", refer to Section 4.3 to ensure a
proper signal is obtained.
More details on hardware configuration can be found in the Ultrasonic Sensing Metrology Subsystem Reference
Design for Water Flow Measurement design guide and an overview video at Getting Started with the
MSP430FR6047 Ultrasonic sensing EVM.
3 Flashing the EVM and Installing the GUI
After you connect the EVM to the PC, flash the latest version of the water metering software to the EVM. You
can use the Uniflash tool to flash the EVM.
1. Install the Uniflash tool on your PC.
2. Install the latest water metering firmware, which can be downloaded from http://software-dl.ti.com/msp430/
msp430_public_sw/mcu/msp430/USSSWLib/USSSWLibWater/latest/index_FDS.html
3. Open Uniflash and select the MSP430FR6047 device.
Figure 3-1. Select MSP430FR6047 Device
4. Choose Connection.
5. Choose image to load. Default image is installed in C:\ti\msp\UltrasonicWaterFR604x_revision_number
\image
6. Click Load Image.
Figure 3-2. Load Image
7. Install the Ultrasonic Sensing Design Center GUI, which can be downloaded from http://software-dl.ti.com/
msp430/msp430_public_sw/mcu/msp430/USSSWLib/USSSWLibWater/latest/index_FDS.html
A shortcut named USS is installed to the Texas Instruments folder in the Windows Start menu to launch the
Ultrasonic Sensing Design Center GUI.
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4 USS GUI
4.1 Connecting to the Platform
After you have installed the GUI and flashed the image to the EVM, run the USS GUI. Connect to the platform by
clicking "Connect" in the "Communications" menu. The GUI reports the connection as shown in Figure 4-1.
Figure 4-1. USS GUI Connected to EVM
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4.2 Configuration Parameters
4.2.1 Basic Configuration Parameters
Figure 4-2 shows the primary configuration parameters.
Figure 4-2. Parameters Tab
The F1, Gap, and Gain parameters are the only parameters which should be initially adjusted. All other
parameters should be set to their default values for 1-MHz transducers. These parameters control the excitation,
amplification, and ADC capture time between the ultrasonic transducers connected to the platform.
Set the "Transmit Frequency" to the nominal frequency of the transducers in kHz (for example, set to 1000 for 1-
MHz transducers). Tune this parameter after the frequency sweep (described in Section 4.5) is conducted. After
the other parameters have been properly determined, tune the transmit frequency to give a better signal
response as described in Section 4.3.
Set the "Gap between pulse start and ADC capture" based on the anticipated ultrasonic time of flight for a given
flow tube with enough additional capture time to address signal shifts due to temperature variations.
The "GUI Based Gain Control" controls the gain of the integrated PGA. Set this parameter to give an ADC
capture of no more than ±900 ADC counts in the ADC capture tab. Although the system should be operable with
signals down to ±150 ADC counts, setting the gain to give higher ADC counts reduces the standard deviation in
measurements.
For example, a DN-25 pipe might have an ultrasonic path which corresponds to a time of flight of approximately
65 µs. This is based on an ultrasonic path between transducers of approximately 9.5 cm and the speed of sound
in water (1450 m/s). An appropriate "Gap" that would ensure there is enough time before the signal to
accommodate shifts due to temperature variations might therefore be 60 µs. The ultrasonic distance between
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transducers will affect how much additional margin is required to address shifts in the signal due to temperature
and flow variations. For example, a pipe with an ultrasonic path of 19 cm might require 10 µs of additional
capture time preceding the signal.
The "Number of Pulses" affects the strength of the signal and the standard deviation of the dToF waveform at
zero flow. An increase in the number of pulses should give a lower standard deviation in dToF. There is also a
tradeoff with respect to power consumption and interference. As the number of pulses is increased, earlier parts
of the excitation signal can interfere with the latter part of the transmitted signal when traveling along alternative
ultrasonic paths. The default setting for this parameter should be used as a starting point.
The "UPS and DNS gap" is the time between upstream and downstream measurements. The time required
between measurements is governed by the ultrasonic propagation time. Larger pipes require a larger gap. There
also needs to be enough time between UPS and DNS excitations to ensure the DNS signal does not have
interference from residual reflections of the UPS signal. The default setting for this parameter should be used as
a starting point.
The "UPS0 to UPS1 Gap" is the time between the end of a set of measurements and the beginning of the next
set of measurements. Power consumption is directly affected by the measurement rate. A UPS0 to UPS1 gap of
1 second consumes roughly twice as much power as a UPS0 to UPS1 gap of 2 seconds. The default setting for
this parameter should be used as a starting point.
Set the "Meter Constant" to give a volumetric result that is consistent with a reference meter under flow.
Specifics on the calibration procedure for determining the meter constant can be found in the "Calibration User’s
Guide". The default setting for this parameter should be used as a starting point.
After the desired set of configuration parameters has been set, you should click the "Request Update" button to
send these parameters to the platform. The "Save Configuration" button will save the current set of parameters
to a file. The "Load Configuration" button loads a previously saved set of configuration parameters from a file.
The timing diagram for the configuration can be seen at the bottom of the GUI screen (see Figure 4-3). The
timing diagram represented in this figure is representative and is not exact.
Figure 4-3. Configuration Timing Diagram
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4.2.2 Advanced Configuration Parameters
The "Advanced Parameters" tab provides access to a variety of more advanced configuration parameters (see
Figure 4-4).
Figure 4-4. Advanced Parameters Tab
Set the "Signal Sampling Frequency" to 3.6 MHz for 1-MHz transducers and 8 MHz for 2-MHz transducers.
Other options including 3.4, 3.8, and 4 MHz can also be used for 1-MHz transducers.
The "Delta ToF Offset" is an adjustment to the differential ToF during the calculation of volume flow rate inside
the ultrasonic flow meter library. Developers can optionally make their custom calculation of the volume flow rate
based on the ToF values provided by the library. See the "Calibration User’s Guide".for more details. The "Abs
ToF Additional Delay" is an adjustment to the absolute ToF to account for any additional delays. The value
depends on the shape of the signal and the envelope threshold. Developers can optionally set this value to zero
and make their own adjustments of the absolute ToF in the application layer.
Increase the "Capture Duration" for configurations with a larger number of pulses, or decrease it for
configurations with smaller number of pulses to ensure the signal is fully captured with enough margin for shifts
over the intended operating temperature range.
The "Interpolation Correction Table Size" determines the number of points used to correct for the interpolation
used in the AbsToF algorithm. Designs requiring more accurate results can use a larger interpolation table. For
details on this table, see the "Calibration User’s Guide".
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The "Algorithm Option" determines which algorithm is used. Only the lobe algorithm is currently available for
water metering. A detailed explanation of how this algorithm works can be found in the Ultrasonic Sensing
Metrology Subsystem Reference Design for Water Flow Measurement design guide.
The "Envelope Crossing Threshold" determines which lobe the AbsToF algorithm will lock onto. Set this
threshold to lock onto the earliest lobe peak that is above the noise. In the example shown in Figure 4-5, this
lobe peak corresponds to a threshold of approximately 22%. Additional information regarding the envelope
crossing threshold can be found in the Optimized ultrasonic sensing metrology reference design for water flow
measurement.
Figure 4-5. Representative Captured Waveform With Interpolation
The “Search Range” parameter is specific to gas algorithms and is not currently used by the “Lobe” algorithm.
"User Param #6" is reserved for future use.
"User Param #10" is reserved for future use.
4.2.3 Conditional Parameters
Modify the following parameters only under specific conditions.
The "ULP Bias Delay" determines when the bias circuit is turned on. The relevant timing diagrams for the
operation of the ULP bias circuit can be found in the MSP430FR58xx, MSP430FR59xx, and MSP430FR6xx
Family User's Guide. For low current consumption, the recommended value is 3.
The “Start PPG Count” determines when the PPG is started. The timing diagrams for the operation of the ULP
bias circuit can be found in the MSP430FR58xx, MSP430FR59xx, and MSP430FR6xx Family User's Guide. For
low current consumption, the recommended value is 10000 nanoseconds. The only scenario in which this value
should be changed is when the time of flight between transducers is less than 30 µs. Use a corresponding
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increase in this parameter to enable more closely spaced transducers. For transducers spaced 25 µs apart,
increase this count to 15000 ns.
The "Turn on ADC Count" determines when the ADC is turned on. The relevant timing diagrams for the
operation of the ULP bias circuit can be found in the MSP430FR58xx, MSP430FR59xx, and MSP430FR6xx
Family User's Guide. Do not modify this parameter.
The "Start PGA and IN Bias Count" determines when the PGA and in Bias Circuit is turned on. The relevant
timing diagrams for the operation of the ULP bias circuit can be found in the MSP430FR58xx, MSP430FR59xx,
and MSP430FR6xx Family User's Guide. Do not modify this parameter.
The “USS XTAL Settling Count” determines how much time is allowed for crystal or resonator settling. Based on
internal experiments, 120 µs is suggested for resonators, and 5000 µs is suggested for crystals.
The "Search Range" parameter is specific to gas algorithms and is not currently used by the "Lobe" algorithm.
4.2.4 Configuration Tuning
After a working configuration has been set, you can experiment with changes to that working set to tune the
system for optimum performance and power. Table 4-1 indicates how changes in specific configuration
parameters change system performance.
Table 4-1. Configuration Tuning
Parameter
Change to Parameter Affects...
Power
Consumption
Flow
Performance
Standard
Deviation Zero Flow Drift
Number of Pulses ✔ ✔ ✔ ✔
UPS0 to UPS1 Gap ✔
GUI Based Gain Control ✔ ✔
Transmit Frequency ✔ ✔ ✔
Envelope Crossing Threshold ✔
Capture Duration ✔ ✔ ✔
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4.3 Capturing the ADC Signals
To capture the ADC signal, go to the "ADC Capture" tab and click the "Capture" button. If you are using and
AudioWell DN-25 meter, you should see a signal that looks like Figure 4-6 at zero flow.
Figure 4-6. Captured ADC Signal
If the capture looks different, check these items first.
• Reduce the gain in your configuration parameters to –6.5 dB. Because the captured signal is windowed, the
tail of the signal may be slightly truncated without changing the results.
• Adjust the Gap between pulse start and ADC capture. Figure 4-7 shows an example where the gap is set too
long. Figure 4-8 shows an example where the gap is set too short.
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Figure 4-7. Gap Between Pulse Start and ADC Capture Set Too Long
Figure 4-8. Gap Between Pulse Start and ADC Capture Set Too Short
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• If no signal is observed, check the transducer connections to the platform. Connect the transducers as shown
in Section 2.
• Be sure that the pipe is filled with water. If no water is in the pipe or the transducers are not connected
properly to the EVM, the captured signal may look similar to Figure 4-9.
Figure 4-9. Captured ADC Signal With No Water or Bad Connection
To save the capture, click the "Save Capture" button and provide a filename. To continuously capture to a file,
click the "Continuous Capture" button and provide a filename.
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4.4 Capturing Waveforms
After you have a good ADC capture, go to the "Waveforms" tab to capture some waveforms. In the "Waveforms"
tab, click the "Start" button to start capturing waveforms. The GUI displays the Delta ToF, Absolute ToF, and
Volume Flow Rate waveforms (see Figure 4-10). Real time statistics are also available below each waveform. A
typical standard deviation value of Delta ToF can be seen in the red box shown in Figure 4-10.
Figure 4-10. Capturing Waveforms
The frequency of measurement updates can be increased by reducing the "UPS0 to UPS1 Gap" in the
"Configuration" tab.
After capturing waveforms for some time, you can save them to a file using the "Save Waveforms" button. The
"Lock All" button stops updates, and the "Reset Graphs" button erases all previously captured data.
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4.5 Frequency Response
The frequency response of the meter can be determined in the GUI to ensure the excitation frequency is optimal.
A "Frequency Sweep" is initiated by first setting the desired starting excitation frequency in the "Configuration"
tab. After this has been set, set the number of "Captures" and "Step Size" to cover the band of interest. In Figure
4-11, the sweep is configured to go from 800 kHz to 1208 kHz. The "Frequency Sweep" button requests a file
name and then initiates the sweep.
Figure 4-11. Frequency Sweep Peak Amplitudes
From this sweep, 1020 kHz appears to be a good excitation frequency for this meter. The process for tuning the
configuration to an optimal value can be summarized as follows:
Note
Steps 1 to 3 should have already been completed in Section 4.3.
1. Set the "Transmit Frequency" to the nominal frequency of the transducer.
2. Adjust the "Gap between pulse start and ADC capture" and "Capture Duration" parameters to capture the
complete signal in the "ADC Capture" window.
3. Adjust the "Gain" setting to get a signal which has an amplitude of ±900 ADC counts.
4. Set the "Transmit Frequency" to a frequency which is 200 kHz less than the nominal frequency of the
transducer and conduct a frequency sweep which ends at a frequency 200 kHz greater than the nominal
frequency of the transducer.
5. Identify the peak amplitude of the "Frequency Sweep" and set the "Transmit Frequency" to this value.
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5 Meter Characterization
Meter characterization comprises standard deviation, zero flow drift, and flow testing.
5.1 Single Shot Standard Deviation
The standard deviation in dToF (and volume) is often used as a measure for the accuracy with which flow
measurements can be made. Although it is possible to average across several measurements, the amount of
time and power required to do this may not meet application requirements.
Standard deviation testing is typically conducted at room temperature over a period of 30 minutes with a
1 measurement per second rate to ensure a statistically valid average. The standard deviation is reported with
the mean in the "Waveform Tab" of the GUI. Figure 5-1 shows the single-shot STD of blocks of 200
measurements. Each plot represents single-shot STD of 200 measurements. The plot clearly shows the variation
of single-shot STD is just ± 2 ps, and the average is < 25 ps.
Figure 5-1. Single Shot Standard Deviation
5.2 Zero Flow Drift Testing
Zero flow drift testing is often used as a measure of the minimum detectable flow of a meter and accuracy in low
flow. The minimum detectable flow of a meter is related to the zero flow drift and the sensitivity of the meter. A
meter with higher sensitivity and lower zero flow drift will have a smaller minimum detectable flow. The minimum
detectable flow is limited by the drift in dToF over temperature. This test is typically conducted in an oven with a
temperature profile ranging from 5°C to 85°C over a period of 4 to 24 hours, depending on the robustness of the
test. These tests are conducted with both the meter and electronics in the oven as well as with just the meter in
the oven to ensure the electronics do not contribute to the drift. More detailed information on zero flow drift
testing can be found in the Ultrasonic Sensing Metrology Subsystem Reference Design for Water Flow
Measurement design guide.
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5.3 Flow Testing
Flow testing is typically conducted with a reference meter and a temperature controlled water circulation system.
Figure 5-2 shows a typical flow test setup. This setup includes a large water tank, two reference meters, and a
Device Under Test (DUT). Flow is recorded at various flow rates by one of the two reference meters and the
DUT. The temperature of the water is varied by addition of ice or hot water to the tank with a thermocouple
recording the water temperature. A video discussing flow measurements and setup can be found at Ultrasonic
Water Flow Meter Demonstration.
Figure 5-2. Flow Test Setup
Flows are typically captured over several minutes and averaged to compare accuracies between a reference
meter and the DUT. Figure 5-3 shows comparative flow tests results for a meter at various flows rates.
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Measurements at room temperature
Figure 5-3. Audiowell Meter Measurements
For more details on water flow testing, see the MSP430FR6047 and Ultrasonic Software Based Water Flow
Meter Measurement Results application report.
6 Revision History
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
Changes from March 28, 2020 to September 17, 2020 (from Revision A (March 2020) to
Revision B (September 2020)) Page
• Added "MSP430FR600x" to list of devices covered by this guide......................................................................2
• Added Section 1.4 ............................................................................................................................................. 2
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