Xylem iRIS 150 GPRS DATALOGGERS - Manual (Page 42)

iRIS 150 V1.11 User Guide - 36
36 iQuest (NZ) Ltd - PO Box 15169, Hamilton, New Zealand Tel: +64 7 857-0810 Fax: +64 7 857-0811 Email: [email protected]
SIG Wind
Speed
+12V Sensor
0V
7.7 Connecting Analogue Wind Instruments
There are a number of wind speed and direction instruments available that interface relatively easily to the
iRIS. This section describes how to connect typical mechanical wind instruments as provided by
manufacturers such as Vector Instruments Ltd or NRG. The anemometer provides pulses that are measured
as a frequency via a digital input. The potentiometer type wind speed instrument provides a 0-5V signal
measured by an analogue input. This however requires an external regulator to provide the 5V supply.
The diagram below shows the required connections for such an installation. The wind speed sensor pulse
output should be connected to a digital input (DI1 or DI2) and the wind direction sensor connected to an
analogue input (AI1 or AI2).
Note also that some wind speed instruments (e.g. the Vector A101M) may require external resistors to
suitably bias the internal electronics. Refer to the manufacturer’s data sheet for details and the appropriate
multipliers and offsets that will be needed.
AI1
DI1
VIN+
GND (-)
A typical sensor configuration example for this type of installation is shown below. The instruments are a
Vector A101M wind speed sensor providing pulses that are converted to metres/sec and a W200P wind
direction sensor. The wind speed and direction are averaged and the results logged every 10 minutes. The
wind speed min and max (lull and gust) are also logged.
* Sensor 1 Cfg
(Now: 3.11)
0 Exit
1 Source [7: Freq 1]
2 Name [Wind Spd]
3 Mode [Period Avg+Min+Max]
4 Multiplier [ 0.010]
5 Offset [ 0.000]
6 Log Multiplier [ 10]
7 Log Rate [10min]
8 Alarms
9 Data * Sensor 2 Cfg
(Now: 176.00)
0 Exit
1 Source [1: Analog1]
2 Name [Wind Dir]
3 Mode [Scalar Avg]
4 Multiplier [ 0.0718]
5 Offset [ 0.000]
6 Log Multiplier [ 1]
7 Log Rate [10min]
8 Alarms
9 Data
SIG Wind
Direction
+5V Sensor
0V
External 12V
Battery +
-
5V
Regulator