Xylem SDI-12 Data Logger iRIS 220, iRIS 320, iRIS 350, iRIS 150, iRIS 300 - Manual (Page 62)

iRIS Datalogger User Guide V1.50
56 iQuest (NZ) Ltd - PO Box 15169, Hamilton, New Zealand Tel: +64 7 857-0810 Fax: +64 7 857-0811 Email: [email protected]
6.8 Connecting SDI-12 Instruments
SDI-12 instruments should be connected as shown in the diagram below. See Section 4.4.3 for information
on using the SDI-12 terminal mode to access SDI-12 instruments directly. Also, refer to Appendix G – SDI-12
for detail on the SDI-12 specification.
TOP iRIS I/O Connector
BOTTOM
An example sensor configuration example for this type of installation is shown below. The instrument is a
standard SDI-12 compatible water level sensor, set to address 0. The level is the first value in the SDI-12
response obtained from the sensor and is read in metres. The offset of 6.177 is the hypothetical offset at the
site to correct the readings to true RL. The corrected level is averaged and the result logged every 15
minutes. The logging multiplier of 1000 is necessary to maintain resolution for the logged data which is
stored in millimetres.
The SDI-12 measurements are taken at a rate determined by the mode of the FIRST SDI-12 sensor
defined in the iRIS. If its mode is Instant, then a measurement is initiated one minute before logging
will occur (e.g. on the 14
th
, 29
th
, 44
th
and 59
th
minute of each hour if the log rate is 15 mins. If the
mode is Period Avg (1) or 1 Min average (4), then measurements are initiated at a rate of 10 seconds (plus
time for measurement to be ready). If a user is logged in via the LCD/keypad, then measurements are taken
at the faster rate no matter what the mode of the first SDI-12 sensor is set to. This allows easy calibration
and checks to be performed.
* Sensor 1 Cfg
(Now: 12.445)
0 Exit
1 Source [15: SDI12,0,1]
2 Name [Water Lvl]
3 Mode [Period Avg]
4 Multiplier [ 1.000]
5 Offset [ 6.177]
6 Log Multiplier [ 1000]
7 Log Rate [15min]
8 Alarms
9 Data
AI4
AI3
AI2
AI1
AGND
AOUT
DIO4
DIO3
DIO2
DIO1
SDI-12
DGND
12V+
GND (-)
VIN+
GND (-)
- +
External
12V Battery
(Optional)
DATA
SDI-12
+12V Instrument(s)
0V
Charging source
e.g. solar panel