Associated with: Many SDI-12 items
The Source attribute is common to many Status displays. The attribute indicates the location at which the item resides. The information shown varies, depending on the item.
The Source attribute displays the value Undefined if the item’s configuration is incomplete, in so far as the device with which the item is associated has not yet been specified.
For SDI-12 Scanners, information is displayed in this format:
<Port>:<Baud Rate>:<Data Bits><Flow Control><Stop Bits>: Sensor <ID>, <Command Type> (<Command/Command Number>) - <Data Length> Measurements
(For many commands, the <Command Number> is excluded if it is zero.)
Example:
COM1:1200:7E1:Sensor 3, Concurrent Measurement with CRC (aCC2!) - 4 Measurements
(For a scanner that is scanning 4 concurrent measurements on sensor number 3. A cyclic redundancy check (CRC) is used to verify that the data received from the sensor is valid. Command Number 2 is used to retrieve the data from the sensor. The scanner uses the channel that communicates via the comms port COM1, at 1200 baud, with 7 data bits, even parity, and 1 stop bit.)
For SDI-12 Analog Points, information is displayed in this format:
<Port>:<Baud Rate>:<Data Bits><Flow Control><Stop Bits>: Sensor <ID>, <Command Type> (<Command/Command Number>):AG <Measurement Offset>
(For many commands, the <Command Number> is excluded if it is zero.)
Example:
COM1:1200:7E1:Sensor 3, Concurrent Measurement with CRC (aCC2!): AG 2
(For the third analog (AG) that the scanner is scanning in a series of concurrent measurements. (The first analog would have an offset of 0, and the second analog an offset of 1.) Scanner details as per the example above.)
In keeping with SDI-12 terminology, the Source attribute uses the following codes to indicate the type of command that is being used to extract the measurements:
| Code | Type of Command |
|---|---|
|
aM! |
Start Measurement |
|
aMC! |
Start Measurement and Request CRC (Cyclic Redundancy Check) |
|
aC! |
Start Concurrent Measurement |
|
aCC! |
Start Concurrent Measurement and Request CRC |
|
aR! |
Continuous Measurements |
|
aRC! |
Continuous Measurements and Request CRC |
|
aV! |
Start Verification |
For more information on any of these commands, see Configure the Sensor Properties.