Measurement-computing PCI-PDISO8 Manuel d'utilisateur télécharger pdf (Page 11)

PCI-PDISO8 User's Guide Functional Details

Isolated inputs

The PCI-PDISO8 has eight isolated input channels. A schematic of a single channel is shown in Figure 8. The

signals are routed through a bridge rectifier so that the inputs are not polarity sensitive.

Figure 8. Isolated input schematic - simplified

Extending the input range

To extend the input range beyond the 5 V to 28 V specified, add an external resistor. Figure 9 shows the resistor

and the equations used to calculate resistor values for a given V

Figure 9. Input range-extending resistor

For more information on digital signal connections

For more information on digital signal connections and digital I/O techniques, refer to the Guide to Signal

Connections. This document is available on our web site at available on our web site at

www.mccdaq.com/signals/signals.pdf).

AC input filter

The inputs are eight individual, optically isolated (500 V) inputs that can be read back as a single byte. The

inputs are not polarity sensitive and may be driven by either AC (50 Hz to 1000 Hz) or DC.

Each input has a software enabled/disabled low-pass filter with a time constant of 5 ms (200 Hz). You enable or

disable each input with InstaCal. The filter is required for AC inputs, and should be used for almost all DC

inputs. Unless you have reason to turn off a filter, you should enable it.

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Measurement-computing PCI-PDISO8 Manuel d'utilisateur Page 11