National Instruments PCI-6509 User Manual

Also see for PCI-6509: Manual User guide

National Instruments PCI-6509 User Manual Manual pdf 11 page image

PCI/PXI/PCIe-6509 User Guide and Specifications | © National Instruments | 11Digital I/OStatic DIO on NI 6509 DevicesThe NI 6509 device provides 96 lines of bi-directional DIO signals, P<0..11>.<0..7>. You canuse each of the NI 6509 DIO lines as a static digital input (DI) or digital output (DO) line. Youcan use static DIO lines to monitor or control digital signals. With the PCI/PXI-6509, each DIOport can be configured as a DI or DO port. The PCIe-6509 can be configured on a line by linebasis. All samples of DI lines and updates of DO lines are software-timed.I/O ProtectionUse the following guidelines to avoid electrostatic discharge (ESD) events and fault conditionssuch as overvoltage, undervoltage, and overcurrent:• If you configure a DIO line as an output, do not connect the line to any external signalsource, ground signal, or power supply.• 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 conditioningsolutions for digital applications that require high current drive.• If you configure a DIO line as an input, do not drive the line with voltages outside of thenormal operating range.• Do not drive the line when the device/system is powered off. Doing so could result inunexpected behavior. Note that the PCIe-6509 Rev C (or later) has protection circuitry inplace to protect against possible unexpected behavior when driving the line under poweroff conditions.• Treat the DAQ device as you would treat any static sensitive device. Always properlyground 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 thePCIe-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.