Interface board for a vision processing unit: multi-port GigE Vision PoE+ camera interface

01

Per-port PoE+ rating against the board's total power budget and 12 V feed

Every four-port board below quotes a per-port PoE+ figure; whether all four cameras can draw it at once depends on the board's own 12 V supply.

ADLINK's PCIe-GIE7xP frame grabbers support IEEE 802.3at PoE+ with power-device detection and classification for classes 0 to 4 at up to 30 W per port, and quote a total PoE power of up to 20 W from the PCIe bus, 60 W from a 4-pin Molex connector and 120 W from a 6-pin Molex connector. The specification table gives a maximum of 61.6 W with either a 4-pin or a 6-pin connector (+12 V at 6 A), 120 W only with both connected (PRO version), and 20 W from the PCIe slot alone (+12 V at 2.1 A); the operating range is 0 to 70 °C at 60 W of PoE but 0 to 40 °C at 120 W. ADLINK also lists PoE overcurrent and overvoltage protection and automatic power budget control. [1]

Neousys's PCIe-PoE354at gives up to 25.5 W per port under IEEE 802.3at-2009, with per-port PoE on/off control, and draws its 12 V for PoE either from the PCIe bus or from an on-board 4-pin connector selected by jumper, up to 9.6 A at 12 V and 1.2 A at 3.3 V; the two-port 352at takes up to 4.8 A at 12 V from the bus only. [2] Basler's four-port GigE interface card lists IEEE 802.3af (up to 15.4 W per port) and 802.3at (up to 25.5 W per port) and a card consumption of 5.0 W. [3]

Editorial calculation: four cameras at ADLINK's 30 W would need 120 W, which only the dual-feed configuration supplies, and then only up to 40 °C; at 25.5 W, four cameras need 102 W, more than the 61.6 W single-feed limit. Neousys's 9.6 A at 12 V is about 115 W of input. From the PCIe slot alone, ADLINK's 20 W covers one camera at 15.4 W but not one at 25.5 W.

List each camera's PoE class and maximum power, the number of cameras per board, the 12 V supply available in the vision unit (slot only, 4-pin or 6-pin), the enclosure air temperature, cable length and category, and whether cameras must be power-cycled individually.

02

Ethernet controllers, bus lanes, cables and timing on four-port boards

Each port is an independent Gigabit link; the board shares one PCIe x4 connection to the processor.

Basler gives a packet-size limit of 8,192 bytes for its ace 2 cameras, with exceptions, against up to 16,332 bytes for its ace 2 5GigE and racer 2 S 5GigE cameras, so the jumbo-frame setting on the board is matched to the camera. [3] ADLINK's PRO versions add firmware-based Trigger over Ethernet with Action Command for synchronising camera acquisitions. [1]

Editorial calculation: four Gigabit ports at 1 Gb/s each total 4 Gb/s, or about 0.5 GB/s, within the 2 GB/s that Neousys gives for its x4 Gen2 bus.

03

Data to send for a vision interface board

Paste it into your enquiry below or into an email to a maker, then replace every bracket.

Cameras: [number; GigE Vision model; PoE class; maximum watts]
Host: [vision unit or PC; slot (PCIe x4, board-to-board); 12 V feed available]
Power: [total PoE budget; per-port on/off; protection]
Data: [frame rate; packet size; IEEE 1588; trigger over Ethernet]
Cabling: [connector (RJ45 or M12 X-coded); category; length]
Environment: [air temperature at the board; airflow]

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