Xylem SDI-12 Data Logger iRIS 220, iRIS 320, iRIS 350, iRIS 150, iRIS 300 - Manual (Page 18)

iRIS Datalogger User Guide V1.50
12 iQuest (NZ) Ltd - PO Box 15169, Hamilton, New Zealand Tel: +64 7 857-0810 Fax: +64 7 857-0811 Email: [email protected]
Figure 6 - iRIS 220 / iRIS320 Digital Input Debounce Links
Figure 7 - iRIS 350 Digital I/O Debounce Links
Digital Outputs
When an iRIS 350 digital I/O channel is configured as an output it can be operated in one of two ways.
Open-drain pull-down capable of sinking up to 100mA at 30Vdc. An integral diode provides transient
protection. Typically this output mode can be used to drive a relay or lamp powered by an auxiliary d.c
supply (e.g. 12V). In this mode, the negative of the load supply must be connected to one of the iRIS GND
terminals.
Although it may appear possible to directly control sensors by switching the sensor negative
supply lead using Digital Output 1 (DIO3 on the iRIS 350), this will introduce measurement
errors and may possibly damage the sensor. Always use Digital Output 2 (DIO4 on the iRIS
350) to power sensors on a timed basis.
Switched 12V output capable of sourcing up to 100mA. Typically this output mode will be used to drive a
sensor, relay or lamp powered by the iRIS 12V supply.
Care should be taken to avoid the load discharging the internal and/or external 12V battery.
Ensure adequate power supply charging capacity is available to cater for the demands of both
the logger and load.
For all models, the digital outputs may be programmed to follow the state of the IP connection so that they
will be active when a wireless IP session has been established. This mode can be used to control power to
an external data radio when using the iRIS as a radio based gateway.
Alternatively, the outputs can also be programmed to follow a schedule for use in powering loads. When
configured to use the scheduled mode, the two outputs have a secondary function.
DI1 debounce
link
DI2 debounce
link
DIO4 debounce
link
DIO1 debounce
link