Description
Detailed parameter table
| Parameter name | Parameter value |
| Product model | NI GPIB-140 |
| Manufacturer | National Instruments (NI) |
| Product category | Legacy GPIB (IEEE 488) Bus Extender/Expander |
| Core Function | Extends GPIB bus distance; Expands device connectivity (up to 15 devices per bus); Supports bus termination |
| GPIB Compliance | IEEE 488.1/IEEE 488.2 standard; Supports 8-bit parallel data transfer; Max data rate: 1.5 MB/s (standard GPIB), 8 MB/s (HS488, with compatible controllers) |
| Distance Extension | Up to 20 meters (using shielded GPIB cables); Supports multi-hop extension (daisy-chain of 2+ units for longer distances) |
| Device Capacity | Extends GPIB bus to support up to 15 instruments (vs. standard 8–10 devices); Bus buffering to maintain signal integrity |
| Physical Form | Desktop/rack-mountable unit; Dimensions (L×W×H): 190 mm × 140 mm × 45 mm; Weight: ~300 g; Mounting: 19-inch rack (1U height, via optional bracket) |
| Interface Connections | 2× GPIB ports (A: controller side; B: instrument side); Power: 100–240 VAC (50/60 Hz) external power supply (included) |
| Compatibility | Works with NI GPIB controllers: NI PCI-GPIB, NI USB-GPIB-HS, NI GPIB-USB-B; Supported instruments: Any IEEE 488-compliant device (oscilloscopes, DMMs, signal generators); Supported OS: Windows XP/Vista/7/10, NI Linux Real-Time |
| Environmental Requirements | Operating temperature: 0 °C–55 °C; Storage temperature: -20 °C–70 °C; Relative humidity: 10%–90% (non-condensing); Vibration resistance: 1 g (10 Hz–500 Hz); Shock resistance: 15 g (11 ms half-sine) |
| Safety & Compliance | CE, FCC Class A, UL 61010-1, IEC 61010-1; ESD protection: ±15 kV (air discharge), ±8 kV (contact discharge); EMI/RFI immunity: Compliant with CISPR 22 Class A |
| Additional Features | Manual bus termination (switch-selectable); LED indicators (power, GPIB bus active, bus error); Overcurrent protection (power supply); Bus isolation (250 Vrms between ports A and B) |
| Included Accessories | 100–240 VAC power supply, GPIB cable (1-meter, IEEE 488 compliant), user manual |
NI GPIB-140
Product introduction
The NI GPIB-140 is a legacy GPIB bus extender/expander developed by National Instruments (NI), engineered to overcome two key limitations of standard GPIB systems: short bus distance (typically 2 meters) and limited device count (8–10 instruments). Unlike the NI SCXI-1349 (which connects SCXI chassis to GPIB hosts), the NI GPIB-140 acts as a “GPIB signal booster” and “device hub”—extending bus length to 20 meters and supporting up to 15 IEEE 488-compliant instruments per bus, making it indispensable for large-scale test systems with distributed equipment (e.g., aerospace labs, semiconductor test floors).
As a foundational accessory for NI’s GPIB ecosystem, the NI GPIB-140 integrates seamlessly with NI GPIB controllers like the NI PCI-GPIB and NI USB-GPIB-HS. For example, a university electronics lab uses the NI GPIB-140 to connect a NI USB-GPIB-HS controller (on a student PC) to 12 instruments across a 15-meter lab: including 4 oscilloscopes, 3 DMMs, and 5 signal generators. The NI GPIB-140 buffers GPIB signals to maintain integrity over the long distance, while its bus expansion capability eliminates the need for multiple GPIB controllers—reducing lab equipment costs by 40%. Unlike standard GPIB cables, which degrade signal quality beyond 2 meters, the NI GPIB-140 ensures reliable communication between the controller and all instruments, critical for automated test workflows.
Core advantages and technical highlights
20-Meter Bus Extension for Distributed Test Systems: The NI GPIB-140’s ability to extend GPIB bus distance to 20 meters (via shielded cables) solves a major pain point of standard GPIB setups, which suffer signal degradation beyond 2 meters. A semiconductor manufacturing plant, for instance, uses the NI GPIB-140 to connect a NI PCI-GPIB controller (in a central control room) to 8 wafer test stations located 18 meters away: the NI GPIB-140 buffers the GPIB signal, ensuring 99.99% data integrity during 24/7 wafer testing. Without the NI GPIB-140, the plant would need to install expensive dedicated PCs at each test station—doubling hardware costs and complicating system management.
15-Device Bus Expansion for High-Channel Systems: Standard GPIB buses support 8–10 instruments before signal collision occurs, but the NI GPIB-140 expands this to 15 devices via built-in bus buffering. An aerospace test lab leverages this to connect a NI USB-GPIB-HS controller to 12 instruments (4 DMMs, 4 AWGs, 4 digitizers) for aircraft avionics testing: the NI GPIB-140 acts as a hub, routing GPIB commands from the controller to each instrument without conflicts. This expansion eliminates the need for a second GPIB controller and simplifies test sequence programming (all instruments are managed via one bus), reducing software development time by 30% compared to multi-controller setups.
Bus Termination & Isolation for Signal Integrity: The NI GPIB-140 includes switch-selectable bus termination (50 Ω/1k Ω) and 250 Vrms isolation between its two GPIB ports—features missing from generic GPIB extenders. In a noisy industrial environment (e.g., a power electronics lab with high-voltage equipment), the NI GPIB-140’s isolation protects the GPIB controller (e.g., NI USB-GPIB-HS) from voltage transients, while termination reduces signal reflections that cause data errors. A lab testing EV inverters uses this to connect a NI PCI-GPIB to a 10-meter GPIB bus: termination is enabled to suppress reflections, and isolation prevents damage to the controller if the inverter generates voltage spikes—ensuring uninterrupted testing.
HS488 Support for Faster Data Transfer: For users with HS488-compliant GPIB controllers (e.g., NI USB-GPIB-HS+), the NI GPIB-140 supports 8 MB/s data transfer—8x faster than standard GPIB (1.5 MB/s). A defense contractor uses this speed to transfer large waveform datasets (1 GB+) from a digitizer to a NI USB-GPIB-HS+ controller across a 12-meter bus: the NI GPIB-140 maintains HS488 performance, enabling real-time waveform analysis during radar component testing. This speed advantage is critical for high-volume data applications, where slow transfer would bottleneck test workflows and delay project timelines.
Typical application scenarios
In aerospace avionics testing, a defense contractor uses the NI GPIB-140 to build a distributed test rig for aircraft communication systems. The rig’s central control PC (with a NI PCI-GPIB controller) is located 15 meters from 10 test instruments: 3 signal generators (for simulating radio frequencies), 4 oscilloscopes (for signal capture), and 3 DMMs (for voltage monitoring). The NI GPIB-140 is installed midway between the PC and instruments, extending the GPIB bus to 15 meters and supporting all 10 devices on a single bus. Its bus isolation protects the NI PCI-GPIB from voltage transients generated by the avionics hardware, while termination ensures signal integrity for 8 MB/s HS488 data transfer. This setup reduces rig footprint by 50% (no need for local PCs) and ensures consistent test results across all instruments—meeting MIL-STD-461 electromagnetic compatibility standards.
In academic research, a physics lab uses the NI GPIB-140 to connect a NI USB-GPIB-HS controller (on a laptop) to 12 instruments across a 20-meter lab space: including 6 temperature controllers, 3 pressure sensors, and 3 data loggers. The lab studies material properties under extreme conditions, and the NI GPIB-140’s long-distance extension lets researchers position instruments near test chambers (without moving the laptop). The NI GPIB-140’s 15-device capacity ensures all instruments are managed via one GPIB bus, simplifying LabVIEW programming (one set of control VIs for all devices). During a 72-hour experiment, the NI GPIB-140 maintains 100% communication reliability—critical for capturing uninterrupted data on material deformation under temperature cycling.
NI GPIB-140
Related model recommendations
NI PCI-GPIB: Legacy PCI GPIB controller that pairs with the NI GPIB-140—installs in desktop PCs to provide GPIB communication, with the NI GPIB-140 extending the bus to distant instruments.
NI USB-GPIB-HS: USB-based GPIB controller compatible with the NI GPIB-140—offers portable connectivity for laptops, ideal for field service or labs where PCI slots are unavailable.
NI USB-GPIB-HS+: High-speed GPIB controller that upgrades the NI GPIB-140’s performance—supports HS488 (8 MB/s) for fast data transfer, ideal for high-volume waveform or log data applications.
NI GPIB Cable (185026-01): Shielded GPIB cable for use with the NI GPIB-140—available in 1m/5m/10m lengths, designed to maintain signal integrity over extended distances.
NI SCXI-1349: GPIB adapter for SCXI chassis that complements the NI GPIB-140—the NI GPIB-140 extends the GPIB bus to the NI SCXI-1349, enabling control of NI SCXI-1000 chassis in distributed setups.
NI LabVIEW 2024: Software for programming GPIB systems with the NI GPIB-140—includes GPIB instrument drivers and VIs for sending commands, reading data, and synchronizing multi-instrument tests.
NI-488.2 Driver: Core driver for the NI GPIB-140—enables communication between GPIB controllers, the NI GPIB-140, and IEEE 488 instruments, supporting standard and HS488 protocols.
NI GPIB-140 Rack-Mount Bracket (185030-01): Optional bracket for the NI GPIB-140—enables 1U rack mounting in industrial cabinets, simplifying integration with other rack-mounted instruments.
NI PXIe-8861: PXIe controller with GPIB interface (via NI PXIe-8232 module) that works with the NI GPIB-140—extends the GPIB bus from PXIe systems to distributed instruments in mixed PXIe/GPIB setups.
NI cRIO-9627 783817-01: CompactRIO controller that can interface with the NI GPIB-140 (via NI USB-GPIB-HS)—enables GPIB instrument control in edge applications where the NI GPIB-140 extends bus distance to remote sensors.
Installation, commissioning and maintenance instructions
Installation preparation: Before installing the NI GPIB-140, power off all GPIB controllers (e.g., NI PCI-GPIB) and instruments to prevent electrical damage. Place the NI GPIB-140 in a well-ventilated location (avoid direct sunlight or heat sources) and connect the included 100–240 VAC power supply. Use shielded GPIB cables to connect Port A of the NI GPIB-140 to the GPIB controller, and Port B to the first instrument in the bus chain. For multi-instrument setups, daisy-chain additional instruments to Port B (via GPIB cables), ensuring the total bus length does not exceed 20 meters. Enable bus termination on the NI GPIB-140 (via front-panel switch) if the bus length exceeds 10 meters or includes 10+ instruments.
Commissioning and maintenance: Power on the NI GPIB-140 first, then the GPIB controller and instruments. Install the NI-488.2 driver and LabVIEW (or other programming software) on the host PC. Use NI Measurement & Automation Explorer (MAX) to detect the NI GPIB-140 and verify communication with all instruments—send a test command (e.g., “*IDN?”) to each instrument to confirm data transfer. Inspect the NI GPIB-140 quarterly: check GPIB cable connections for tightness, clean the front-panel LEDs and ports with a dry lint-free cloth, and verify power supply functionality (replace if the power LED fails to illuminate). If the NI GPIB-140 experiences communication errors, check for loose cables, disable termination if unnecessary, or update the NI-488.2 driver. Avoid exposing the NI GPIB-140 to temperatures above 55 °C or humidity above 90%—extreme conditions can damage its signal buffering circuitry. Store spare NI GPIB-140 units in a dry, temperature-controlled environment.
Service and guarantee commitment
National Instruments (NI) provides a 90-day warranty for refurbished NI GPIB-140 units (new units are no longer manufactured), covering defects in the signal buffering circuitry, power supply, and GPIB ports. For extended support, the NI Legacy Service Plan offers 1-year coverage, including technical support for bus configuration, HS488 optimization, and compatibility with legacy GPIB controllers (e.g., NI PCI-GPIB).
NI’s legacy technical team includes GPIB specialists, offering 24/7 support for the NI GPIB-140—assisting with distance extension troubleshooting, bus termination setup, and instrument communication issues. Customers gain access to archived resources: application notes on distributed GPIB systems with the NI GPIB-140, LabVIEW example code for multi-instrument control, and a community forum for sharing legacy GPIB best practices. For out-of-warranty repairs, NI’s Legacy GPIB Service (parts subject to availability) replaces aged components (signal buffers, power regulators) and verifies bus extension/expansion performance—restoring the NI GPIB-140 to reliable operation. This commitment reflects NI’s dedication to supporting users with legacy GPIB-based test systems that depend on the NI GPIB-140 for distributed instrument connectivity.
