PCI/PXI/PCIe-6509 User Guide and Specifications
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© National Instruments
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Digital I/O
Static DIO on NI 6509 Devices
The NI 6509 device provides 96 lines of bi-directional DIO signals, P<0..11>.<0..7>. You can
use each of the NI 6509 DIO lines as a static digital input (DI) or digital output (DO) line. You
can use static DIO lines to monitor or control digital signals. With the PCI/PXI-6509, each DIO
port can be configured as a DI or DO port. The PCIe-6509 can be configured on a line by line
basis. All samples of DI lines and updates of DO lines are software-timed.
I/O Protection
Use the following guidelines to avoid electrostatic discharge (ESD) events and fault conditions
such as overvoltage, undervoltage, and overcurrent:
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If you configure a DIO line as an output, do not connect the line to any external signal
source, ground signal, or power supply.
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If you configure a DIO line as an output, understand the current requirements of the load.
Do not exceed the output limits of the DAQ device. NI has several signal conditioning
solutions for digital applications that require high current drive.
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If you configure a DIO line as an input, do not drive the line with voltages outside of the
normal operating range.
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Do not drive the line when the device/system is powered off. Doing so could result in
unexpected behavior. Note that the PCIe-6509 Rev C (or later) has protection circuitry in
place to protect against possible unexpected behavior when driving the line under power
off conditions.
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Treat the DAQ device as you would treat any static sensitive device. Always properly
ground yourself and the equipment when handling the DAQ device or connecting to it.
I/O Pull-Up/Pull-Down Resistors (PCIe-6509 Only)
The PCIe-6509 has user-configurable pull-up and pull-down resistors. The DIO lines on the
PCIe-6509 are connected to an NI ASIC that contains a weak pull-down resistor (47 k
,
typical), and each DIO line is connected to a software-selectable strong pull-up resistor (4.7 k
,
typical), as Figure 5 shows.
