Product Overview
The National Instruments PCI-6517 is an industrial digital input and output card for PCI systems. It is designed to interface 24 V industrial logic signals with a desktop or industrial computer. The card provides isolated digital input lines and isolated sourcing digital output lines for monitoring sensors, switches, and relays and for driving industrial loads.
The PCI-6517 is part of the NI industrial digital I/O product family. It is used in factory automation, machine control, test stands, and laboratory monitoring where robust, isolated digital interfacing is required. The card installs in a PCI slot and is supported by NI-DAQmx software for configuration and programming.
Isolated Digital Input and Output
The card provides isolated digital inputs and sourcing digital outputs for 24 V industrial signals. Isolation between field wiring and the computer helps protect the host from transient voltages and ground potential differences that are common in industrial installations. This improves reliability when the card is connected to machinery, contactors, and externally powered devices.
Sourcing outputs supply the positive side of the circuit to the load. The outputs are designed to drive industrial loads within their specified current limits. Engineers should verify output current, load type, and inductive load protection requirements for each application, and should add suppression for relays and solenoids.
Industrial Control Features
The PCI-6517 includes features that support safe and predictable operation. Change detection allows the card to report when an input line changes state, reducing the need to poll inputs continuously. A watchdog timer can place outputs in a defined state if the host application stops responding, helping protect equipment in unattended systems.
Programmable power up states define the condition of digital outputs when the system starts, which is important in machine control where an output must not activate unexpectedly at power on. These features make the card suitable for applications that require more than simple static digital I/O.
PCI Integration and Wiring
The PCI-6517 installs in a compatible PCI slot in a desktop or industrial computer. It connects to field wiring through compatible terminal blocks and cables. Proper wiring practice is important in industrial environments: use shielded cable where appropriate, separate signal wiring from high current power lines, and confirm common references for each group of isolated channels.
Output wiring should include appropriate fusing and protection for the connected loads. Cable routing away from power conductors reduces induced noise, and secure connector fastening reduces intermittent faults on vibrating machinery. These practices improve reliability and simplify maintenance.
Software and System Integration
The PCI-6517 is supported by NI-DAQmx driver software. It can be programmed with LabVIEW, LabWindows/CVI, Measurement Studio, and other NI-DAQmx compatible development environments. NI-DAQmx provides configuration tools for digital lines, change detection, watchdog settings, and power up states, which helps reduce development time and improves consistency.
The card can be combined with analog input and other digital I/O in the same application. Engineers can build test sequences that measure conditions, evaluate logic, and drive outputs in a defined order. Data logging and event handling can be implemented with standard NI software tools.
Typical Applications
Industrial machine control and monitoring
Relay, solenoid, and indicator driving
Limit switch and sensor status monitoring
Automated test stand digital sequencing
Watchdog protected output applications
Factory automation and laboratory interfacing
The PCI-6517 provides isolated industrial digital input and sourcing output channels for 24 V loads in a PCI card. Its change detection, watchdog timer, programmable power up states, and NI-DAQmx support make it a practical card for industrial control applications.
