Measurement-computing PCI-DIO96H Uživatelský manuál stáhnout pdf (Strana 16)

PCI-DIO96H User's Guide Functional Details

Pull-up and pull-down resistors

The PCI-DIO96H board has open locations where you can install a 2.2 K , eight-resistor single inline package

(SIP) resistor network for each port. The locations are marked PORT#A, PORT#B and PORT#C (RN10 through

RN21), and are adjacent to the I/O connector. PORT0A corresponds to FIRSTPORTA, PORT1A corresponds

to SECONDPORTA, etc, as shown on the pinout diagram.

The SIP is made up of eight 2.2 K resistors. One side of each resistor is connected to a single common point and

brought out to a pin. The common line is marked with a dot or line at one end of the SIP. The remaining resistor

ends are brought out to the other eight pins (refer to Figure 4).

2.2 KOhm SIP

Dot

(LO or HI)

I/O Lines

Figure 4. Eight-Resistor SIP Schematic

The SIP may be installed as pull-up or pull-down. At each RN# location, there are 10 holes in a line. One end of

the line is +5V, the other end is GND. They are marked HI and LO respectively. The eight holes in the middle

are connected to the eight lines of a port.

 For a pull-up function, mount the SIP with the common pin (marked with a dot or line) in the HI position.

 For a pull-down function, mount the SIP with the common pin in the LO position.

When installing pull-up and pull-down resistor SIP packs, we recommend using a 2.2 K, eight-resistor SIP

(MCC part number SP-K2.29C).

Unconnected inputs float

Unconnected inputs typically float high, but not reliably. If you are using a PCI-DIO96H board for input and

have unconnected inputs, ignore the data from those lines. You do not have to terminate input lines, and

unconnected lines will not affect the performance of connected lines. Ensure that you mask out any

unconnected bits in software.

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Measurement-computing PCI-DIO96H Uživatelský manuál Strana 16