Xylem H-3521 - Manual (Page 16)

2-6 Installation
H-3521
2.7 Wiring and Installation Precautions
! The H-3521 requires that the water be at ground potential. Mother Nature takes care of this
for surface and ground water.
! Make certain the pressure port connection is tight
! Make certain the sintered bronze vent port is not painted or covered
2.8 Programming Your SDI-12 Data Recorder
You must prepare your data recorder to receive and record the H-3521 data. Since data recorders
differ widely, refer to your recorder manufacturer's directions. In general, program the data
recorder to input four values via the SDI-12 port. Usually only one or two of the parameters are
actually recorded. Your data recorder must issue an “aM!” command, then collect the data with a
“aD0" command, as explained in Chapter 4. The H-3521 places four parameters in its data
buffer:
a+AA.AAA+BB.BBB+CC.C+DD.D
Where:
a = SDI-12 address 0-9, A-Z
AA.AAA = Stage (feet, inches, meters etc.)
BB.BBB = Pressure (PSI)
CC.C = Temperature (C)
DD.D = Input Supply Voltage (Volts)
2.9 Programming the SDI-12 Address
If more than one sensor is to be connected to the SDI-12 bus, make certain each sensor has a
different sensor address. The H-3521 comes from the factory with its address set to “0". The
address can be edited using the RS-232 menu interface or using an extended SDI-12 command.
Refer to chapters 4 and 5 for more details.
2.10 Programming the H-3521 Sensor
The H-3521 comes from the factory with the following programmable settings:
SDI Address: 0
Slope : 2.3067 (feet of H
2
0)
Offset : 0.00
MeanCount : 16
Power_Mode: 0 (Sleep)
4-20ma_Hi: 20.0 (Ft)
4-20mA_Lo: 4.0 (Ft)
With these values the Stage will be in units of feet when used in clean water. The slope can be
changed to accommodate other engineering units such as inches or meters. The setups are stored
in EEPROM within the H-3521 and will not be lost if the power is disconnected. The extended
commands for changing these setups are described in detail in Chapter 5 and most of these