MASSA PRODUCTS CORPORATION
Product Manual- April 24, 2012 26 M3 Wireless Ultrasonic Level Sensor
APPENDIX F
M3 Application Software – Understanding an Ultrasonic Waveform
This very important tool will allow diagnosing more difficult applications and also allows recording the tanks ultrasonic
profile for archival purposes.
When the dia.yml configures obtain_diagnostic_data_enable: 'false', waveforms and other data are stored in the gateway.
Save the file from the gateway to your PC and use the M3 Application software (see www.massa.com) to recall each
waveform. See plot below of a typical waveform.
A waveform can be broken down in 3 sections. The 1
st
pulse on the left in the waveform is from the sensor ping (or
ultrasonic transmit) that emits the sound wave. It is then followed by a reflection (next pulse to the right of the ping pulse)
off the surface and finally followed by other multiple reflections that may or may not be present. The sensor is designed to
ignore the ping pulse and capture the 1
st
reflected signal over threshold to report the range to the surface (the red line in the
waveform represents the signal capture threshold level). Other multiple reflections are ignored. Ideally the signal between
the transmit pulse at the beginning of the waveform and the 1
st
reflected signal of the actual surface level needs to be clear
of unwanted reflections. Unwanted reflections could be caused by items such as ladders in a tank, the sensor being
mounted right next to the edge of the tank or the sensor not being level and pointing towards the edge of the tank or other
items. In more difficult applications, the Sensor Sensitivity adjustments could provide a solution, but consult with Massa
Products for support (record and provide all waveforms as indicated in Table 1 with an empty tank). As you can see in the
waveform below, the 1
st
reflection is at 60” and it is clear from the ping pulse to this reflection (good!). An example of a
problematic situation is for a pulse being present at 40” which could represent an item such as pipe in the direct path.
Sound will travel around objects such as pipes for the bigger reflection such as the liquid surface.
If it is observed that a sensor model does not have a reliable reflection (1.25V peak at least) in an empty tank (or lowest
process level) while operating with the highest power mode, then it may be necessary to select a lower frequency model
sensor. Consult with Massa Products for more information.
NOTE: Model M3/150 has 2 waveforms as seen in Appendix A, all other models have 4 waveforms.
NOTE: The iDigi Device Integration Application (Dia) software provides a rich python library for addressing remote data
acquisition, control, and presentation of device data on ConnectPort X gateways. Dia collects data from any device which
can communicate with a Digi gateway, over any gateway interface and re-presents this data to upstream applications in a
fully customizable approach. Digi recommends that you start your device networking application with Dia.
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