Connecting Devices To The Analog Outputs; Output Voltage Range; Signal Connection; External Interrupt Input - Measurement Computing PC-CARD-DAC08 User Manual

PC-CARD-C37F/26 cable is pin compatible with the PCM-DAC08 using the
PCM-C37/33 cable.

3.2 CONNECTING DEVICES TO THE ANALOG OUTPUTS

The analog outputs are single-ended. You must avoid potentials between signal
ground and chassis ground on your computer. If you are using a laptop and are on
battery power, the computer is floating with respect to earth ground, but the laptop is
on the charger unit or on wall power, the laptop may be grounded.
Whenever the computer is grounded, you must connect signals so there is no potential
between PC ground and signal ground. If there is a potential, it will be added to the
signal. For example, if your card is supplying 3.5 volts and there is a potential of
-1.5V between the PC and the sensor ground, your device under control will be
reading 2.0V instead of 3.5V

3.3 OUTPUT VOLTAGE RANGE

There is only one output voltage range, ±5VDC.

3.4 SIGNAL CONNECTION

Loads drawing higher currents than the maximum current specified in the electrical
spec will cause the analog output to drop, meaning that a code of 4095 will not be able
to generate a full scale voltage of 5V, but somewhat less.

3.5 EXTERNAL INTERRUPT INPUT

Pin 14 on the 26 pin I/O mini-connector is an external input which will generate an
interrupt to the computer. The interrupt must be enabled through software. The
interrupt is falling edge triggered using TTL level signals. The procedure initiated by
an interrupt is wholly dependent on programming.
3.6 DIGITAL INPUTS & OUTPUTS
The PC-CARD-DAC08 has eight bi-directional digital I/O lines. The eight digital
lines can be programmed as input or output in groups of: eight inputs, eight outputs or
four inputs and four outputs. A register controls the direction of the digital I/O lines
and must be set via software. At power-on or reset, the digital lines are set as inputs.
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