Xylem iRIS 150 GPRS DATALOGGERS - Manual (Page 34)

iRIS 150 V1.11 User Guide - 28
28 iQuest (NZ) Ltd - PO Box 15169, Hamilton, New Zealand Tel: +64 7 857-0810 Fax: +64 7 857-0811 Email: [email protected]
7 Sensor Connection Examples
7.1 Connecting a Flow Meter or Rain Gauge
One of the most common uses for the iRIS is logging data from pulse sources such as flow meters or rain
gauges. Connecting such devices to the iRIS is very simple – wire the switch between the appropriate digital
input (DI1 or DI2) and a ground (GND) terminal. Both of the digital inputs provide a “wetting current” for
clean contact sources, but transistor switches and active signals (ones that supply a voltage) can also be
used. If a transistor switch is used, connect the collector (+) to the digital input and the emitter (-) to the
GND. See Section 4.2.4 for details on the digital inputs and using the debounce link.
Both inputs can be used simultaneously and each input has three associated totalisers, which are viewable
from the LCD. See Section 6.2.4.6. These totalisers operate even if the input is not configured as a source
to one of the six virtual sensors.
The diagram below shows the typical connection diagram for such an installation. It assumes the use of DI1
as the pulse input channel. The external power source can be any d.c supply from 6V to 15V.
DI1
GND
+VIN
GND (-)
The sensor should be configured for the correct channel, scaling and logging regime as described in Section
5.3.3. Event mode (Sensor Mode=2) can be used to reduce the quantity of data logged, especially for
rainfall where the actual data density is low.
Three typical sensor configuration examples for this type of instrument are shown below. The instrument is a
0.5mm tipping bucket rain gauge (TBRG) and is logged every 15 minutes for examples 1 and 2.
Flow Meter
or
Rain Gauge
External power source e.g 12V battery
* Sensor 1 Cfg
(Now: 0.0)
0 Exit
1 Source [3: Pulse1]
2 Name [Rainfall]
3 Mode [Instant]
4 Multiplier [ 0.500]
5 Offset [ 0.0000]
6 Log Multiplier [10]
7 Log Rate [15min]
8 Alarms
9 Data * Sensor 1 Cfg
(Now: 0.0)
0 Exit
1 Source [3: Pulse1]
2 Name [Rainfall]
3 Mode [Event]
4 Multiplier [ 0.500]
5 Offset [ 0.0000]
6 Log Multiplier [10]
7 Log Rate [15min]
8 Alarms
9 Data
* Sensor 1 Cfg
(Now: 0.0)
0 Exit
1 Source [3: Pulse1]
2 Name [Rainfall]
3 Mode [Event]
4 Multiplier [ 0.500]
5 Offset [ 0.0000]
6 Log Multiplier [10]
7 Log Rate [0min]
8 Alarms
9 Data
Example 1: Normal Timed
This logs the total every 15
minutes, even if it is zero. This
produces the most data as
every “time slot” has an
associated sample. Example 2: Timed Event
This logs the total every 15
minutes only if it is non-zero. It
also inserts a zero record, one
log interval earlier, if required. Example 3: True Event
This logs every event to a one
second resolution. If there is
more than one count in a
second, the total is logged. No
zero samples are logged.