Massa M3 Manual de usuario descargar pdf (Pagina 8)

MASSA PRODUCTS CORPORATION June 11, 2013

Product Manual 7 M3 Wireless Ultrasonic Level Sensor

8.2.1.1 Host Command to M3: Read Data History Buffer, Command #1

To access the Data History Buffer, the command format show here can access up to 8 previously recorded events in one RF

message. An address pointer byte is the location of the 1

st

block of data to recall. Up to 8 total blocks can be requested. There are

a total of 111 events that can be recorded in the sensor. Oldest data will be overwritten, so you must take note of the data

collection interval and obtain the data from the sensor before it is lost (by being overwritten). The message format is shown here

and is sent to the gateway by the host.

Sensor ID Host ID 7 1 Data Ptr # of event blocks checksum

default=1 default=251 1 to 111 1 to 8

Address pointer byte can be from 1 to 111 where 1 is the most recent data block saved by the sensor and 111 was the oldest block

in memory. Here are a few examples:

Example 1: To retrieve the most recent 4 recorded events, set AddrPtr byte=1 and EventsToRetrieve byte=4.

Example 2: To retrieve Events 8 through 13, set AddrPtr byte=8, EventsToRetrieve byte=6.

Example 3: To retrieve Event 111 only, AddrPtr byte=111, EventsToRetrieve byte=1.

Note: The MAC address is the M3’s Sensors XBee radio’s address and is sent before the main message to the Digi gateway as shown in this

format above. See 8.2.16 for information on obtaining sensor’s MAC address.

8.2.1.2 Response from M3 to a “Read Data History Buffer” request Command #1

The M3 responds to the Read Data History Buffer request by sending up to 8 blocks of the recorded data from its Data History

Buffer memory to the host device. The Digi Gateway sends the data to the host device as shown below. This is also the same

format for the automated outgoing message when a sensor wakes up from Deep Sleep when enabled.

Host ID Sensor ID total # of bytes 1 Data Ptr # of event blocks oldest record newest record checksum

default=251 default=1 of this message 1 to 111 1 to 8 (8 bytes) (8 bytes)

The Data History Buffer block in the message is 8 bytes long and is recalled in the format shown below. Up to 8 of these blocks

can be recalled within a RF message with the last recorded event being placed first in the message. See Section 6 for the

definition of each byte.

NOTE: RangeMSB = 255 represents a cleared data record even though there may be data in the other bytes.

8.2.2.1 Host Command to M3: Acquire New Event Data without recording to Data History Buffer, Command #2

Command #2 requests the Sensor to acquire a new measurement without recording to the Data History Buffer memory. The

message format is shown here 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 2 checksum

default=1 default=251

8.2.2.2 Response from M3 to a “Acquire New Event Data without recording to Data History Buffer” Command #2

The M3 responds to the “Acquire New Event Data without recording to Data History Buffer” command by sending a newly

acquired event data block and not store it in the Data History Buffer. See format below.

Host ID Sensor ID 13 2 8 bytes checksum

default=251 default=1 see below

The format of this 8 byte Event Data block is shown below. See Section 6 for the definition of each byte.

NOTE: The event bytes EventLSB and EventMSB will be returned with a zero.

Massa M3 Manual de usuario Pagina 8