Xylem H-4161 - Manual (Page 30)

3-14 SDI-12 Command and Response Protocol
H-4161
3.14 Extended Read/Write Monitored Address and Read/Write Monitored Parameter
As a data monitor, the H-4161 passively monitors the communication between the data recorder
and it’s SDI-12 sensors. The H-4161 waits for, and collects a specified data parameter from a
specified sensor. The data is scaled and used to set the H-4161's 4-20mA output. These four
commands allow the user to examine or set the sensor address and the sensor data parameter to
be monitored. At the factory the monitored address is set to “Z” and the monitored parameter is
set to “1". For example: with these settings if a data recorder collects data from sensor “Z” with
a “ZD0" command and the sensor transmits Z+123.4+24.3, the value 123.4 will be
captured by the H-4161. Note: the monitored address setting is not used if Module Mode = 1
(initiate).
Do not set the Monitored Address to the same address as the H-4161's address. The address and
parameter settings are stored in non-volatile Flash memory. Once a new value is written to the
Flash memory, a copy is sent to the sensor data buffer for verification. This setting can be
viewed by using a subsequent "D" command. To verify these settings any other time, use the
"XRMA" or “XRMP” commands. This command takes 1 second to complete and places 1 value
in the data buffer.
Command Response Description
"aXRMA!" “a0011" Read current monitored address
"aXRMP!" “a0011" Read current monitored parameter
"aXWMAn!" “a0011" Write current monitored address
"aXWMPn!" “a0011" Write current monitored parameter
Where: a is the sensor address ("0-9", "A-Z", "a-z", "*", "?").
XRMA are upper case characters.
XRMP are upper case characters.
XWMA are upper case characters.
XWMP are upper case characters.
n is the new address or parameter
Example of a H-4161 Extended Read Monitored Address command:
Command Response Time Values Description
"aXRMA!" "a0011" 1 sec 1 Read monitored address
Command Response Description
"aD0!" "a+Z" Monitored address = Z
Example of a H-4161 Extended Write Monitored Address command:
Command Response Time Values Description
"aXWMA5!" "a0011" 1 sec 1 Write monitored address
Command Response Description
"aD0!" "a+5" Monitored address = 5