In the field of industrial machine vision and automation inspection, USB3 Vision has quickly become one of the mainstream choices for camera interfaces due to its plug and play, high bandwidth (5Gbps), and low-cost cables. However, multi camera systems often face challenges such as USB controller bandwidth competition, insufficient power supply, and hot swappable reliability. The ADLINK PCIe-U300 series frame acquisition card provides a professional level solution for multi camera vision systems by integrating multiple independent USB 3.0 controllers, a power supply capability of up to 1500mA per port, and software programmable power management. This series includes 4-port (U304), 8-port (U308), and 12 port (U312) models, all based on PCIe x4 Gen2 bus, ensuring sufficient transmission bandwidth for each port. This article will provide engineers with a detailed operation guide from the aspects of hardware selection, power supply planning, installation configuration, status diagnosis, and common troubleshooting, to help them efficiently deploy a stable USB3 Vision acquisition system.
Product series and selection criteria
The core advantage of the PCIe-U300 series is the use of four independent Fresco FL1100 USB 3.1 Gen 1 controllers, each connected to an x4 Gen2 (5 GT/s) bus through a PCIe switch. This design enables:
U304 (4 ports): Each port has an exclusive controller, which does not interfere with each other and is suitable for high bandwidth, low latency applications (such as multiple high-speed cameras simultaneously capturing data).
U308 (8 ports): Two ports share one controller (4 controllers in total), suitable for medium load scenarios.
U312 (12 ports): Among them, 8 ports are similar to U308, and the other 4 ports are led out through internal 20 pin expansion interfaces and need to be used with expansion brackets, suitable for high-density and low-cost deployment.
When selecting, it is necessary to comprehensively consider the number of cameras, single camera bandwidth (resolution/frame rate), and total power requirements. If there are four or more 5-megapixel @ 60fps cameras, U304 is more secure; If it is mostly a low bandwidth camera or intermittent acquisition, U308/U312 is more cost-effective.
USB power supply capability and power planning
1. Power supply specifications for each port
Front panel Type-A port: 5V ± 5%, maximum 1500mA
U312 expansion port (internal interface output): 5V, maximum 900mA
The typical power consumption of industrial USB cameras is 3-6W( 5V@600 ~1200mA), Therefore, 1.5A per port is sufficient to cover most models. However, it should be noted that if cameras with additional loads (such as circular light sources) are used, they may need to be downgraded.
2. Total power budget and power source
The USB power supply on the card is converted from the+12V provided by the PCIe slot of the host, and there are two types of power sources:
Only PCIe slots (without 4-pin Molex) can provide a maximum total power of 20W. In this mode, if all four ports of U304 are full (4 × 5V × 1.5A=30W), it has exceeded the limit, and the actual current of each port needs to be limited or only some ports need to be used.
External 4-pin Molex (CN10): can provide additional power to increase the total USB output capability to:
U304/U308: Maximum 30W
U312: Maximum 60W
Recommended practice: As long as the system load exceeds 20W, be sure to connect a 4-pin Molex auxiliary power supply (12V input, at least 4A output), otherwise it may cause system restart or USB device disconnection due to insufficient power supply. The Molex connector pins are defined as: 1=+12V, 2=GND, 3=GND, 4=+5V (this 5V is reserved, and the actual power supply is still converted from 12V). A cable of 16AWG or above is required for connection.
3. Overcurrent protection (OCP)
Each USB port is equipped with a hardware current limit. When the current exceeds the rated value (approximately 1700mA ± 7% for ports 1-81100mA ± 7% for ports 9-12), the port automatically cuts off power supply. After triggering, the host needs to be restarted to recover, and cannot be reset through software. Therefore, it is necessary to ensure that the nominal current of each camera is lower than the rated value and leave sufficient margin.
4. Software programmable power switch
ADLINK provides AVS SDK (USB Power Management API), which allows users to individually turn on or off the power supply to each port through the software. This is extremely useful when the camera is deadlocked or requires remote reset, without the need for physical cable plugging and unplugging. The example code only needs to call a few lines of API to implement, simplifying system maintenance.
Hardware installation and interface layout
1. Physical installation
Insert the card into a PCIe x4, x8, or x16 slot (occupying x4 bandwidth) and secure the bezel.
U312 precautions: In addition to the 8 USB ports on the front panel, there are also 4 ports that are led out through the onboard 20 pin internal pin header. The accompanying expansion bracket cable needs to be connected to this connector and the bracket needs to be fixed in the idle PCI board position of the chassis.