CompactRIO Chassis

NI CompactRIO Chassis

What Is a CompactRIO Chassis?

A CompactRIO chassis is a modular I/O platform that accepts compatible NI C Series modules. Depending on the model, it can provide an FPGA, timing resources, network communication or a dedicated expansion interface for connection to an external CompactRIO controller or host computer.

Unlike an integrated CompactRIO controller, a CompactRIO chassis is primarily used to add modular I/O capacity. It should not be assumed to provide the same local processor, operating system or standalone application capability as a controller.

CompactRIO Chassis Architectures

CompactRIO Chassis Families

Model families include multiple FPGA, slot-count, interface and lifecycle variations. Verify the exact model, part number, installed options and required software before selecting a new chassis or replacing existing hardware.

CompactRIO Chassis and Controller Relationship

A CompactRIO chassis expands the I/O capacity of a larger system. The connected controller or host provides the application-level processing, while the chassis provides C Series module slots and model-specific timing or FPGA resources.

The complete architecture must define how data, clocks, triggers and FPGA logic are shared between the controller and the chassis. The connection method is a system design decision, not only a cable-selection decision.

How to Choose a CompactRIO Chassis

1. Identify the Required Expansion Architecture

Begin with the existing controller or host hardware. Determine whether the chassis must connect through Ethernet, a dedicated RIO expansion interface or another supported CompactRIO architecture. Do not select a chassis before confirming how it will communicate with the rest of the system.

For replacement projects, record the existing chassis model, controller model, cable assembly, network topology, LabVIEW project and FPGA target before proposing a substitute.

2. Define the C Series Module Configuration

Select the required NI C Series modules according to the electrical interface of the sensors and devices under test. Common requirements include analog voltage, current, thermocouples, RTDs, strain, IEPE vibration sensors, digital I/O, counters and industrial communication.

Confirm slot count, module support, signal conditioning, isolation, sample timing and terminal accessories. A C Series module may be physically similar to another module while requiring different excitation, connectors or driver support.

3. Determine FPGA Requirements

Use the chassis FPGA for functions requiring deterministic hardware-level behavior, such as custom triggering, encoder processing, pulse generation, inline filtering, fast protection logic, protocol implementation and synchronized I/O.

FPGA resource availability depends on the exact chassis model. Existing FPGA code may require recompilation or redesign when changing the chassis, even if the C Series module layout remains the same.

4. Plan Timing and Synchronization

Specify whether the remote I/O must share a sample clock, reference clock, start trigger or timestamp with the controller, other chassis or external equipment. This is especially important for motion, power, vibration, control and closed-loop applications.

Ethernet connectivity by itself does not guarantee deterministic synchronization. Confirm the supported timing architecture, cable routing, network configuration and software implementation for the exact hardware combination.

5. Review Data Throughput and Latency

Calculate the generated data rate from the active channel count, sample rate and transferred data format:

Data rate = active channels × sample rate × transferred bytes per sample.

Include network or expansion-bus overhead, FPGA buffering, controller processing, logging and other simultaneous system traffic. Continuous dynamic acquisition and closed-loop control should be validated with the intended application and test duration.

6. Confirm Deployment Conditions

CompactRIO chassis are commonly installed in machinery, test cells, vehicles, cabinets and laboratory fixtures. Confirm power input, operating temperature, cooling, mounting, shock and vibration conditions, cable strain relief and field-wiring practices before installation.

Software, FPGA and Compatibility Considerations

CompactRIO chassis are configured through compatible NI software, commonly including NI-RIO, LabVIEW, LabVIEW Real-Time and LabVIEW FPGA. The exact supported software depends on the chassis, connected controller, operating system and C Series modules.

Before deployment or replacement, verify:

• Exact chassis model, revision and part number
• Connected CompactRIO controller or host model
• Required cable, remote interface or Ethernet topology
• Installed C Series modules and slot assignments
• LabVIEW, NI-RIO, LabVIEW Real-Time and LabVIEW FPGA versions
• Existing FPGA target, bitfile and required compilation process
• Clock, trigger, synchronization and latency requirements
• Controller storage, data logging and network-transfer requirements
• Power, temperature, mounting and field-wiring conditions

Typical CompactRIO Chassis Applications

• Distributed industrial I/O and machine monitoring
• Remote sensor acquisition in test cells and facilities
• Hardware-in-the-loop simulation systems
• Automotive, aerospace and transportation validation
• Power electronics, motor and inverter testing
• Custom FPGA timing and protocol development
• Structural, strain, force and vibration monitoring
• Energy, battery and renewable-energy control systems
• Robotics, motion coordination and mechatronics
• CAN, LIN and industrial communication integration
• Legacy CompactRIO expansion and maintenance projects

CompactRIO Chassis vs CompactRIO Controller

A CompactRIO controller combines embedded processing, real-time software support, FPGA capability and C Series I/O slots in one device. A CompactRIO chassis is normally used to provide additional or distributed C Series I/O capacity under the control of a compatible controller or host system.

Choose an integrated CompactRIO controller when the system requires a self-contained embedded control platform. Choose a CompactRIO chassis when the design requires remote I/O expansion, dedicated FPGA chassis resources or compatibility with an existing CompactRIO architecture.

Legacy CompactRIO Chassis Replacement

Replacing a legacy CompactRIO chassis requires more than matching the number of C Series slots. The replacement may use a different FPGA family, remote interface, power requirement, synchronization method, driver version or deployed software architecture.

Compare the following before approving a replacement:

• Controller-to-chassis connection architecture
• FPGA target, resources and compiled bitfile
• C Series module support and I/O mapping
• Clock, trigger and synchronization behavior
• Network topology, switches and IP configuration
• NI-RIO and LabVIEW software compatibility
• Power connectors, field wiring and mounting arrangement
• Environmental rating and operating temperature requirements
• System requalification and safety documentation

Production or safety-related systems should be revalidated with the complete controller, chassis, module and application configuration. Physical compatibility does not guarantee software or FPGA compatibility.

CompactRIO Chassis Procurement and RFQ Guide

FAQ

Does a CompactRIO chassis include an embedded controller?

Not necessarily. A CompactRIO chassis is generally used as modular I/O expansion and may require a compatible CompactRIO controller or host system. Verify the exact model architecture before assuming that it can run an application independently.

Can a CompactRIO chassis use C Series modules?

Yes. CompactRIO chassis accept compatible NI C Series modules for analog, digital, sensor and communication I/O. Confirm support for the exact chassis, connected controller and software version.

Can an Ethernet CompactRIO chassis operate through any network switch?

Not automatically. The switch, network topology, traffic load, security configuration and required timing behavior must be compatible with the complete CompactRIO application. Validate the intended network before deployment.

Do I need to recompile an FPGA bitfile when changing chassis?

Usually, yes, if the replacement uses a different FPGA target or architecture. Review FPGA resource use, target compatibility and I/O mapping before moving an existing application to another chassis.

Can a CompactRIO chassis replace a CompactDAQ chassis?

Only when the complete system architecture supports it. CompactRIO chassis are intended for FPGA-based and embedded control architectures, while CompactDAQ chassis are primarily used for PC- or network-based modular data acquisition.

How do I choose between a CompactRIO chassis and an integrated CompactRIO controller?

Choose an integrated controller for a self-contained embedded real-time and FPGA system. Choose a chassis when the requirement is expansion I/O, remote placement or compatibility with an existing controller and FPGA architecture.

Related NI CompactRIO Solutions

NI CompactRIO Chassis from PXISOURCE

PXISOURCE supports engineers, system integrators and procurement teams with CompactRIO chassis selection, controller compatibility review, C Series module matching, FPGA migration checks and legacy-system replacement. Send the existing controller and chassis models, I/O list, timing requirements, software environment and preferred hardware condition for a technically matched quotation.