National Instruments NI USB-6509 Industrial DIO Features

NI 6509 User Guide and Specifications 20 ni.com

Pins 49 and 99 supply +5 V power to the I/O connector. The power drawn

from these two pins shares the power consumption with the transceivers.

The I/O connector power has a fuse for overcurrent protection. This fuse is

not customer replaceable. If the fuse is blown, return the device to NI for

repair.

Caution The power pins, +5V and GND, connect to the computer power supply and are

not isolated. Do not connect a +5V power pin directly to GND or connect a +5V or GND

pin to any other voltage source. Doing so may cause injury or permanently damage the

NIUSB-650 9 components. National Instruments is not liable for any damage or injury

resulting from such a connection.

For more information on maximum power ratings and overcurrent limits,

refer to the Specifications section.

Industrial DIO Features

The NIUSB-6 509 features digital filtering, programmable power-up

states, change detection, and a watchdog timer.

Use the digital filter option available on the NI USB-6509 input lines to

eliminate glitches on input data. When used with change detection, filtering

can also reduce the number of changes to examine and process.

You can configure the digital input channels to pass through a digital filter,

and you can control the timing interval the filter uses. The filter blocks

pulses that are shorter than half of the specified timing interval and passes

pulses that are longer than the specified interval. Intermediate-length

pulses—pulses longer than half of the interval but less than the

interval—may or may not pass the filter.

Table3 lists the pulse widths guaranteed to be passed and blocked.

You can enable filtering on as many input lines as is necessary for your

application. All filtered lines share the same timing interval, which ranges

from 200 ns to 200 ms.

Table 3. NI USB-6509 Digital Filtering

Filter Interval

Pulse Width Passed Pulse Width Blocked

Low Pulse High Pulse Low Pulse High Pulse

tinterval tinterval tinterval tinterval/2 tinterval/2