Optiquest iRIS 320 - Manual (Page 56)

iRIS 220 / iRIS 320, V1.19 User Guide - 54
54 iQuest (NZ) Ltd - PO Box 15169, Hamilton, New Zealand Tel: +64 7 857-0810 Fax: +64 7 857-0811 Email: [email protected]
AI4
AI3
AI2
AI1
AGND
5VOP
DI2
DI1
DO2
DO1
SDI-12
DGND
12V+
GND (-)
VIN+
GND (-)
6.2 Connecting a 0-5V Pressure Transducer
Connecting a standard sensor (such as a pressure transducer that provides a 0-5V signal) to an iRIS is
relatively straightforward. The sensor can be powered from the iRIS 320’s 12V supply and optionally
controlled by a digital output to save power.
However, the iRIS 320’s internal battery is NOT recommended for directly powering the sensor alone if the
charging source is a solar panel, as it is a relatively low capacity type. Connect a supplementary external
12V battery (7A/Hr or larger) to increase the available storage.
The diagram below shows the typical connection diagram for such an installation. It assumes the use of AI1
as the desired input channel. It also shows the connection of a transistor switch module with control from
DO1.
TOP
BOTTOM
iRIS I/O Connector
The sensor should be configured for the correct channel, scaling and logging regime as described in section
4.3.8.
NOTE: The iRIS supports activation of one or both digital outputs with a schedule. See section 4.3.12
for more details and an example. Therefore, if further power reduction is to be achieved by
controlling the transducer power, follow this procedure:
1.
Install a transistor switch module in series with the transducer power lead and control it from
one of the digital outputs. See Appendix A for details on the transistor switch module.
2.
Configure the digital output’s mode to be Schedule (Mode = 1).
3.
Set up the digital output’s schedule to match the sensor’s logging period, but with the digital
output being set to activate the desired amount of time before the sensor is to log and with
sufficient “on” time to ensure an overlap with the logging time.
4.
Ensure the sensor mode is set to 0 (Instant).
+
Signal Pressure Transducer
-
Optional
Transistor
Switching
Module
Charging source e.g solar panel
- +
External
12V Battery
(Required)