ADLINK PCIe-PXIe-8638 High Speed PXIe Bus Expansion Scheme

This transparency is achieved through hardware underlying implementation, thus bringing three significant advantages:

No need for additional drivers: There is no longer a need to install specialized bus drivers for the expansion kit itself, avoiding system instability caused by driver version mismatches or conflicts.

Plug and play: During system startup, the host BIOS and operating system can automatically discover and configure all modules in the remote PXIe chassis, just like enumerating local PCIe devices.

Excellent compatibility: Any standard PXIe module can work properly on this extended system without any modifications. This is crucial for protecting users' existing module investments and software assets.

Multi chassis expansion solution: building a large-scale testing system

When the number of slots in a single PXIe chassis (usually 17 or 18 slots) cannot meet the requirements of large testing systems, the PCIe-PXIe-8638 series provides two validated and reliable expansion topologies.

1. Daisy Chain Topology

The topology structure is simple and the deployment cost is low. Using PXle-8638D as an intermediate node, connect PCIe-8638 on the host PC to the upper port of PXle-8638D on the first chassis, and then connect from the lower port of this module to PXle-8638D (or standard PXle-8638) on the second chassis, and so on.

Application advantage: Suitable for testing production lines with a linear increase in the number of devices, all chassis on the link share the total bandwidth of a PCIe x8 connection with the host. The wiring and configuration in this way are very intuitive.

Configuration points: It should be noted that the total bandwidth of the entire link is limited by the x8 connection from the host card to the first chassis. Therefore, it is not recommended to connect too many chassis on the same link to avoid bandwidth becoming a bottleneck.

2. Star Chain Topology

The star topology provides the best bandwidth and scalability flexibility. In this configuration, multiple PCIe-8638 host adapter cards need to be installed on the host PC (limited by the number of PCIe slots on the host), and each card is connected to an independent PXIe chassis through a separate cable. If the PXle-8638P module is used, the expansion level can also be deepened to enable the expansion of another chassis on the peripheral slot of one chassis.

Application advantage: Each chassis can obtain independent, dedicated, and interference free PCIe x8 full bandwidth. This topology provides the highest total throughput and system parallelism, making it the optimal solution for building multi-channel parallel acquisition or simulation systems.

Deployment scenario: For example, in a radar signal simulation system with multiple channels, each PXIe chassis can independently simulate a set of phased array antenna signals, and the host can achieve phase accurate collaborative simulation through parallel control of multiple PCIe-8638 cards.

Engineering Deployment Guidelines and Key Considerations

To ensure the long-term stable operation of the system, engineers need to pay attention to the following points when deploying the PCIe PXIe-8638 suite:

Mechanical installation and heat dissipation

The PCIe-8638 on the host side is a low profile card, and if installed in a standard sized chassis, it may be necessary to replace the accompanying full height blank.

The module on the PXIe end (PXle-8638/P/D) complies with the PXI-5 PXI Express hardware specification Rev. 2.0. Its working temperature range is from 0 ° C to 55 ° C. When deploying high-density, high-power PXIe module chassis, it is important to ensure that the chassis' cooling fans are working properly and that the ambient temperature does not exceed this range. The storage temperature ranges from -40 ° C to 71 ° C, ensuring the reliability of the product during transportation and storage.

Cable management and signal integrity

PCIe Gen 2 high-speed signals are highly sensitive to impedance matching of transmission lines and external interference. Although the ACL-PCIEX8 series cables provided by ADLINK have been fully shielded, in actual wiring, it should be avoided to tie extension cables parallel to strong electrical cables (such as motor drive lines, AC power lines) or near high-power electromagnetic interference sources (such as frequency converters, relays).

The maximum supported extension distance is 5 meters. If a longer distance is required, theoretically it is not recommended to simply extend the cable, as this can cause signal attenuation and a sharp increase in jitter, which may lead to link training failure or data errors. At this point, the use of fiber PCIe expansion solutions should be considered as an alternative.

System configuration and initialization

After setting up the system or modifying the topology for the first time, it is recommended to ensure that all modules are physically connected securely before powering on the PXIe chassis and host PC.

Due to the hardware transparency of the system, there is usually no need for special settings in the BIOS. But if the host is a PC designed specifically for testing and measurement, it is recommended to disable unnecessary power-saving features (such as PCIe link power management) in the BIOS to ensure that the link will not experience response delays due to entering a low-power state during rigorous continuous testing tasks.