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MASSA PRODUCTS CORPORATION June 11, 2013

Product Manual 8 M3 Wireless Ultrasonic Level Sensor

8.2.3.1 Host Command to M3: Acquire New Event Data and record to Data History Buffer, Command #3

Like Command #2, Command #3 requests the Sensor to acquire a new measurement and records to the Data History Buffer. The

message format is shown below and is sent to the gateway by the host. This command is typically used when the Data Collection

Register is 0 (manual mode).

Sensor ID Host ID 5 3 checksum

default=1 default=251

8.2.3.2 Response to “Acquire New Event Data and record to Data History Buffer” Command #3

The response to Command #3 is similar to Command #2 but with the measurement recorded to the Event Data History Buffer.

Unlike Command #2, this command will reply with Event Data Counter values. The Digi Gateway sends the data to the host

device as shown below.

Host ID Sensor ID 13 3 see below checksum

default=251 default=1 8 bytes

The format of this 8 byte Event Data block is shown below. See section 6.1 for the definition of each byte.

NOTE: The event bytes EventLSB and EventMSB will be retrieved from Sensor memory.

8.2.4.1 Host Command to M3: Acquire Ultrasonic Waveform, Command #10

To acquire an ultrasonic signal profile from the sensor for diagnostic purposes, Command #10 obtains a waveform and stores it in

sensor memory. The reply response will be the retrieval of this data and will require 28 RF messages containing the data to

complete the transfer (see next section).

The Ultrasonic Waveform operation is controlled by two Configuration Register locations. The sensor gain control is set by

Configuration Register 110 and the number of transmit cycles is set by Configuration Register 109. These registers must be set

prior to sending Command #10. See sections 9.2.10 and 9.2.11 for the details of these Waveform Configuration Registers. Here

is the format of the message which begins the acquisition.

Sensor ID Host ID 5 10 checksum

default=1 default=251

8.2.4.2 Response to “Acquire Ultrasonic Waveform” Command #10

In response to Command #10, the sensor collects waveform data and sends back configuration registers, firmware versions, and

waveform data. Since the RF message length is limited to 64 bytes, it will take 28 RF messages in total for complete transfer of

the data. An “Acknowledge” command from the host device to the sensor will indicate when to send the next block. The initial

response from the sensor after the acquire waveform request is to send Data Block #1 followed by subsequent blocks as shown

below. If a data block is not received by the host device, a ‘Re-Send’ command can be sent to the sensor.

Sensor sends a block of 64 data bytes to the Host

Host ID Sensor ID 70 10 block # 64 data bytes checksum

default=251 default=1 1 to 28

Host sends an ‘Acknowledge’ message back to the Sensor after receiving and saving the block of 64 data bytes

Sensor ID Host ID 6 200 10 checksum

default=1 default=251 Acknowledge

Host sends a ‘Resend’ message back to the Sensor if data was corrupt or if it did not receive data

Sensor ID Host ID 7 201 10 1 to 28 checksum

default=1 default=251 Re-Send

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