Vaisala Hydromet Data Collection Platform - Manual (Page 149)

Chapter 5 ____________________________________________________________ Technical Data
VAISALA______________________________________________________________________ 147
Digital I/O Module QMI118
The QML logger provides the possibility to extend the I/O capacity with
the optional digital I/O module (QMI108 or QMI118) equipped with
eight inputs and eight outputs. The digital I/O module interfaces to the
logger via the SPI connector. The module is located inside the enclosure
beside the logger, and it conforms to the same environmental immunity
and emission standards as the logger.
The module has eight open collector outputs with 30 VDC / 1 A
continuous drive capability and LED indicators. The eight inputs of the
module tolerate voltages from 0 to 25 VDC (the absolute maximum
30 VDC), and they have 40 ms (typical) contact debouncing circuitry.
The module allows connection of slow pulse inputs, for example, with
tipping bucket rain gauges.
The later version, QMI118, is otherwise the same as QMI108 except
there are four open collector outputs and four outputs with high side
switching capability. This means the module can switch, for example,
+VB directly to the peripheral that needs it without additional relays.
The rating of the high side outputs is the same as open collector outputs,
30 VDC / 1 A. They have a common positive terminal labeled +VB.
The voltage does not have to be system battery voltage but can vary
from 3.3 V to 30 V.
Note that the GND pin associated with the output block of O4 ... O7
(both blocks in QMI108) should always be wired to the system GND if
any of the outputs are used to switch currents that exceed 10 mA.
Table 36 Technical Data QMI108/118
Property Description/Value
Max. voltage all outputs, +VB 30 VDC
Max. current all outputs 1 A
Max. voltage all inputs 25 V
Input default state ON (max. 100 k weak pull up to 3.3 V
built in)
Input debounce duration 40 ms typ., 60 ms max.
Input threshold 2 V
Input hysteresis 300 mV