Xylem SDI-12 Data Logger iRIS 220, iRIS 320, iRIS 350, iRIS 150, iRIS 300 - Manual (Page 63)

57 iQuest (NZ) Ltd - PO Box 15169, Hamilton, New Zealand Tel: +64 7 857-0810 Fax: +64 7 857-0811 Email: [email protected]
6.9 Connecting Quadrature Encoders
A commonly used type of digital water level instrument is one that provides two pulse outputs, the direction
of movement being determined by the phase difference between the two signals. The iRIS tracks these
steps and therefore the relative water level.
These instruments are passive and do not require a power supply. This implementation makes use of the
two digital inputs, DIO1 and DIO2 (DI1 and DI2 on the iRIS 220/320) as the reference channel and auxiliary
channels respectively.
The installation differs between the older iRIS 220/320 and the current iRIS 350. The following two sections
describe how to incorporate a quadrature sensor on these models.
6.9.1 iRIS 350 Installation
On the iRIS 350, this software version which emulates an iRIS 320 does not leave any digital inputs
available for use with another sensor such as a rain gauge or flow meter. However, future versions will make
DIO3 and/or DIO4 available for such a purpose as the hardware will support this.
The diagram below shows the connections for an installation with an iRIS 350. The debounce links for DIO1
and DIO2 (DI1, DI2) should be fitted.
If the direction is incorrect, reverse the two channels.
TOP iRIS 350 I/O Connector
BOTTOM
- +
External
12V Battery
(Optional)
B Quadrature
A Shaft
Encoder
COM
Charging source
e.g. solar panel
AI4
AI3
AI2
AI1
AGND
AOUT
DIO4
DIO3
DIO2
DIO1
SDI-12
DGND
12V+
GND (-)
VIN+
GND (-)