METER TEROS 21 - Operation; Safety Precautions for Operation; Sensor Installation Guide

6
Example 1 1I!113METER␣ ␣ ␣TER21␣389631800001
Parameter
Fixed
Character
Length Description
1I!
3
Data logger command
Request to the sensor for information from sensor address 1.
1
1
Sensor address
Prepended on all responses, this indicates which sensor on the bus is returning
the following information.
13
2 Indicates that the target sensor supports SDI-12 Specification v1.3
METER␣ ␣ ␣
8
Vendor identification string
(METER and three spaces ␣ ␣ ␣ for all METER sensors)
TER21␣
6
Sensor model string
This string is specific to the sensor type.
For the TEROS 21, the string is TER21 .
389
3
Sensor version
This number divided by 100 is the METER sensor version
(e.g., 389 is version 3.89).
631800001
≤13,
variable
Sensor serial number
This is a variable length field. It may be omitted for older sensors.
CHANGE ADDRESS COMMAND aAB!
The Change Address command is used to change the sensor address to a new address. All other commands
support the wildcard character as the target sensor address except for this command. All METER sensors
have a default address of 0 (zero) out of the factory. Supported addresses are alphanumeric (i.e., a–z, A–Z, and
0–9). An example output from a METER sensor is shown in Example 2, where the command is in bold and the
response follows the command.
Example 2 1A0!0
Parameter
Fixed
Character
Length Description
1A0!
4
Data logger command.
Request to the sensor to change its address from 1 to a new address of 0.
0
1
New sensor address.
For all subsequent commands, this new address will be used by the
targetsensor.
ADDRESS QUERY COMMAND (?!)
While disconnected from a bus, the Address Query command can be used to determine which sensors are
currently being communicated with. Sending this command over a bus will cause a bus contention where all
the sensors will respond simultaneously and corrupt the data line. This command is helpful when trying to
isolate a failed sensor. Example 3 shows an example of the command and response, where the command is in
bold and the response follows the command. The question mark (?) is a wildcard character that can be used in
place of the address with any command except the Change Address command.
Example 3 ?!0
Parameter
Fixed
Character
Length Description
?!
2
Data logger command.
Request for a response from any sensor listening on the data line.
0
1
Sensor address.
Returns the sensor address to the currently connected sensor.