Description
Agilent E8491B | IEEE-1394 VXIbus Controller / Interface Module, In Stock
Architect’s Product Breakdown
The Agilent E8491B operates as a high-performance IEEE-1394 (commonly known as FireWire) VXIbus interface and controller module designed for C-size mainframes. Widely utilized in automated test systems, aerospace test benches, and modular instrumentation setups, this module acts as the bridge between external PC-based controllers and the internal VXIbus backplane, enabling rapid command execution and high-throughput data acquisition.
Because legacy ATE systems depend on specific driver stacks and physical interface standards, replacing a faulty unit requires matching the exact E8491B part number and ensuring the host controller’s IEEE-1394 card and VISA libraries are correctly configured to maintain communication with the mainframe.
E8491B
Key Technical Specifications
| Parameter | Specification |
| Series | Agilent / HP VXIbus Controller and Interface Line |
| Model / Part Number | E8491B |
| Form Factor | C-Size, 1-slot VXIbus module (typically occupies Slot 0) |
| Interface Protocol | IEEE-1394 (FireWire) serial bus |
| Data Transfer Rate | High-speed serial communication supporting rigorous ATE throughput demands |
| Software Compatibility | Agilent VISA, SICL, and standard VXI plug-and-play drivers |
| Operating Environment | Designed for standard rack-mount and industrial test laboratory conditions |
Field Engineer’s Pitfall Guide
- WARNING: Hot-Plugging IEEE-1394 Cables. Connecting or disconnecting the FireWire cable while the VXI mainframe or host computer is powered on can cause electrostatic discharge spikes, destroying the interface transceiver chip.
- WARNING: Improper Slot Positioning. Installing the controller module outside of designated Slot 0 (where system timing and bus arbitration lines reside) will prevent the mainframe from booting or recognizing downstream instruments.
- WARNING: Driver and OS Mismatches. Attempting to run legacy E8491B hardware on modern operating systems without proper legacy IEEE-1394 OHCI host controller drivers will result in constant communication timeouts.
- Field Anecdote: I remember an aerospace test rack failing to initialize because a replacement E8491B interface was plugged into Slot 2 instead of Slot 0, completely breaking the VXI backplane arbitration sequence.
QA & Testing SOP
- Visual & Origin Verification: Inspect the front-panel connector ports, metal shielding, and rear VXI DIN connector pins for bent pins, debris, or thermal wear, and verify original Agilent nameplate markings.
- Test Bench Environment: Insert the module securely into Slot 0 of a certified C-size VXI mainframe and connect it via an cable to a test PC running Agilent Connection Expert.
- Communication & Bus Verification: Execute VISA IO configuration scans and diagnostic self-tests to ensure error-free link establishment, proper register access, and stable backplane communication.
- Anti-Static & Protective Packaging: Enclose the module in anti-static shielding and pack it tightly inside high-density structural foam to protect the protruding front ports and rear pins during shipment.
Technical FAQ
What interface standard does the Agilent use to connect to the computer?
It uses the (FireWire) serial interface standard to connect the VXI mainframe to an external host controller or PC.
Can the be placed in any slot within the VXI mainframe?
No. As a system controller module, it is specifically designed to occupy Slot 0 of the C-size VXIbus mainframe to manage backplane timing and bus arbitration.
Is the still actively manufactured?
No. The is obsolete and discontinued by Keysight Technologies. Certified refurbished units and replacement parts are available through specialized test and measurement suppliers.
What causes communication loss between the PC and the VXI mainframe?
Communication loss is typically caused by a faulty cable, outdated or corrupted VISA/SICL driver installations, or a damaged transceiver port on the module.
