What Is the Power-Up State of My Digital Input/Output (DIO) Board?
Hardware: Legacy DAQ Devices>>Digital I/O>>PC-DIO-96
What is the power-up state of my digital input/output (DIO) board and how do I change it?
The default power up states are shown in the table below. If they are selectable, please refer to Chapter 3 of your hardware's product manual (see the related link below) in the section titled "Digital I/O State Selection" for instructions on how to select your desired state. The table below lists the default power-up state for some DIO devices.
The PCI-DIO-96, PXI-6508, and PCI-6503 contain bias resistors that control the state of the digital I/O lines at power up. At power up, each digital I/O line is configured as an input, pulled either high or low by a 100 kΩ bias resistor.
On the PCI-DIO-96, all of the 100 kΩ bias resistors pull up. Therefore, the default power-up state of each line on the PCI-DIO-96 is high.
On the PXI-6508 and PCI-6503, you can select the direction of the 100 kΩ bias resistors. Set jumper W1 to high to configure the resistors as pull-up resistors. Set jumper W1 to low to configure the resistors as pull-down resistors.
You can change individual lines from pulled up to pulled down—or, on the PXI-6508 and PCI-6503, from pulled down to pulled up—by adding your own external resistors.
Product Manual: PCI-DIO-96/PXI-6508/PCI-6503 (March 2009)
Product Manual: PC-DIO-24/PnP (February 1998)
KnowledgeBase 266KK6YF:& Can I Use a Pull-down Resistor to Set the Default State of the Digital Lines on my NI DAQ Device
Report Date: 11/20/1998
Last Updated: 07/26/2016
Document ID: 1FJ84OU3