Xylem H-4161 - Manual (Page 28)

3-12 SDI-12 Command and Response Protocol
H-4161
3.12 Extended Read/Write Module Mode command
The H-4161 operates in one of two modes: MONITOR or INITIATE. When the Module Mode =
0 (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. When the
Module Mode =1 (initiate), the H-4161 actively initiates measurements and collects the response
from the sensor attached to the auxSDI port. The specified data parameter is scaled and used to
set the H-4161's 4-20mA output.
These two commands allow the user to examine or change the Module Mode. The H-4161 comes
from the factory with Module Mode = 0 (monitor). The Module Mode 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 this setting any other time, use the "XRMM" command. This command takes 1 second to
complete and places 1 value in the data buffer.
Command Response Description
"aXRMM!" “a0011" Read current module mode
"aXWMMn!" “a0011" Write the module mode
Where: a is the sensor address ("0-9", "A-Z", "a-z", "*", "?").
XRMM are upper case characters.
XWMM are upper case characters.
n 0 = MONITOR, 1=INITIATE
Example of a H-4161 Extended Read Module Mode command:
Command Response Time Values Description
"aXRMM!" "a0011" 1 sec 1 Read module mode
Command Response Description
"aD0!" "a+0" Module Mode is MONITOR
Example of a H-4161 Extended Write Module Mode command:
Command Response Time Values Description
"aXWMM1!" "a0011" 1 sec 1 Write module mode
Command Response Description
"aD0!" "a+1" Module Mode is INITIATE