Vaisala HydroMet User's Guide download pdf (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

1 2 ... 144 145 146 147 148 149 150 151 152 153 154 ... 159 160

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Vaisala HydroMet User's Guide Page 149