Product Overview
The National Instruments PCI-6704 is an analog output card for PCI based computers. It provides 32 analog output channels with 16 bit resolution. The card is designed for applications that require many analog command signals, such as industrial control, multi channel stimulus, valve and actuator driving, and hardware in the loop test.
The PCI-6704 is part of the NI analog output product family. It installs in a standard PCI slot and is supported by NI-DAQmx software. Its high channel count makes it suitable for panels and test systems that must generate many independent analog signals from one computer.
Voltage and Current Output
The card supports voltage output and current output modes depending on the configuration and the connected load. Voltage output is common for driving analog inputs and controllers, while current output is used for current loop devices in industrial systems. Engineers should confirm the supported ranges and load limits for the specific card configuration.
Each channel provides 16 bit resolution, which supports fine adjustment of output levels. Engineers should verify settling time and output noise for the required application, especially when driving high capacitance or inductive loads. External protection may be needed for loads that can feed voltage back into the output.
Multi Channel Output
Thirty two output channels in one card allow many actuators or signal inputs to be controlled from a single PCI slot. This reduces the number of separate cards and cables required in a test rack. Engineers should plan channel mapping carefully so that each output is associated with a known device and function.
Output updates can be software timed or hardware timed depending on the application. Hardware timed updates support repeatable sequences across multiple channels, which is useful for coordinated stimulus and control profiles. Engineers should document the update timing and any synchronization between channels.
PCI Integration and Wiring
The PCI-6704 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: use shielded cable where appropriate, separate output wiring from sensitive analog inputs, and confirm common references for the connected devices.
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-6704 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 output ranges, timing, and channel scaling, which helps reduce development time and improves consistency.
The card can be combined with analog input and digital I/O in the same application. Engineers can build test sequences that set outputs, wait for settling, measure responses, and evaluate results. Data logging and event handling can be implemented with standard NI software tools.
Typical Applications
Multi channel actuator and valve control
Industrial control and process simulation
Hardware in the loop test
Current loop device driving
Multi channel stimulus generation
PCI based test and control systems
The PCI-6704 provides 32 channels of 16 bit analog output in a PCI card. Its channel count and support for voltage and current output make it suitable for multi channel control and stimulus applications.
