Choosing a camera interface when more than one profile passes the bandwidth check

In short

The calculator's list is a shortlist of transports; the decision then rests on four things it does not weigh: the run from camera to host, the topology, meaning one connection per camera or a shared network, the power path, and the hardware in the PC. Take them in that order, because the run length screens cables before a port plan is worth drawing. For four 5 MP cameras at 60 frames per second the page states four 5GigE network ports, one per camera connection, while the core returns three 5GigE host channels, which is aggregate capacity rather than an allocation: two of these streams ask 4.81 Gbit/s of a channel budgeting 4.50 Gbit/s (calculated). Wire four 5GigE ports with one stream each, or two 10GigE channels with two, then confirm cable, power and host hardware on part numbers.

What the bandwidth screen settles, and what it leaves open

The interface check turns resolution, frame rate, pixel format and camera count into a stream in Gbit/s and compares it with each profile's useful budget. It returns the transports whose budget covers the requested image payload; the board and its slot, processor load, switch capacity, packet loss and drivers are outside it (calculated, core scope). Each row carries its own basis, and the reference page's older USB3 and CXP-12 figures are not the ones the calculator applies today.

Start from the run between camera and host

Distance is usually already decided by the machine, so apply the last column first. A reference length screens candidates: it names the one cable basis behind the profile, not every cable that can be qualified for it. The CoaXPress standard ties the maximum to the rate and the cable type, and a JIIA-listed CXP-12 series is certified in lengths up to 35 m (standard; certified-cable record). A 30 m run therefore does not delete USB3 or Camera Link from the list; it turns the question into a cable check. Find the part number qualified for that profile at that length, active or optical if that is what it takes, and read its rating, which belongs to the cable rather than to the family.

Decide the topology before you count ports

The calculator returns three counts that answer different questions. Camera connections keep one host-side connection per camera. Host channels, on a network profile, are the total stream divided by one channel's useful budget and rounded up: a lower bound on aggregate capacity, not a plan for which stream lands where. Physical lines count Camera Link links or CoaXPress lanes; for network profiles the field stays empty, which is not zero cables (calculated).

Write the allocation yourself, one stream at a time, treating each camera stream as indivisible: it runs over one channel or not at all. Two streams that each need more than half a channel's budget cannot share it, however much capacity three channels add up to in total. Aggregating links does not repair that, since aggregation distributes whole flows between members rather than splitting one (vendor documentation, Cisco EtherChannel). A switch changes where the ports sit, not the arithmetic: its per-port mapping, uplinks and backplane have to carry the allocation, and cameras can equally land on PC ports directly.

Power on the same cable, and when it needs its own path

Power belongs to the camera and the equipment at the other end, never to the interface name. USB can combine data and bus power when the record says so, and MV-CH120-60UC states support for USB 3.0 power supply (datasheet). Power over Ethernet, camera power on the network cable, works only when the camera and the switch or injector both implement it, and not every GigE camera does (interface guide, Edmund Optics). Power over CoaXPress is defined at 13 W per cable at a nominal 24 V, a limit per cable rather than per camera: a device that draws more can be fed over several connections or from its own supply (standard, JIIA CXP-001-2021). Camera Link has both branches too: Power over Camera Link feeds a compatible camera through a compatible frame grabber and a PoCL-rated cable (industry reference, A3; vendor documentation, Euresys). Where any of the three parts lacks that rating, the camera takes power separately.

What the host has to carry

USB3 and Ethernet cameras are listed with no dedicated capture board, Camera Link requires a capture card, and CoaXPress runs through an interface card or frame grabber, the host board that receives the image stream (interface guide, Edmund Optics; vendor documentation, Basler). "No dedicated board" is not "no host hardware to plan".

Four USB connections do not prove four host controllers. Cameras on one controller or hub share it and its link to the PC, so several fit when the documented total covers their combined stream, and separate controllers are what you buy when it does not (vendor documentation, Basler Bandwidth Manager; Teledyne multi-camera note). On Ethernet the same applies to adapters, switch ports and uplinks, sized for the allocation rather than the sum. Our catalog separates cables for GigE, USB3, CoaXPress and Camera Link from frame grabbers.

Worked example: one 5 MP stream at 60 fps, then four of them

Four cameras sit 3 m from the PC, each running a full frame of 2448 × 2048 pixels at 60 frames per second in Mono8, a monochrome format with eight bits on the wire per pixel. Those values are assumptions of this example.

One camera produces 2.40648192 Gbit/s (calculated), and twelve of the sixteen profiles cover it; FastEthernet, GigE, Camera Link Base and 2.5GigE fall out on that single stream. Four such cameras total 9.62592768 Gbit/s (calculated), the same twelve pass, and the counts separate them.

Those three columns come from the calculation core and its API (calculated). The page itself answers in camera connections: here its recommendation reads "4 5GigE network ports required", and its comparison sizes every profile against four connections rather than showing the host-channel column.

Read the 5GigE row for what it is: three is 9.62592768 divided by 4.50, rounded up (calculated), the capacity the host needs in total and nothing about which camera uses which channel. Two of these streams make 4.81296384 Gbit/s (calculated), more than the 4.50 Gbit/s of one channel, so the wired scheme is four 5GigE ports with one stream each. On 10GigE the two channels do allocate, since 4.81296384 fits the 9.00 Gbit/s budget, provided the switch, its uplink and its backplane are sized for that pairing. USB answers the same arithmetic at the connection: one USB3 Gen 1 connection budgets 3.60 Gbit/s (calculated), so two of these streams do not share one such connection or uplink. A controller or hub behind it has its own documented total, and the streams put on it are summed against that figure.

The physical-line column is the rest of the parts list: eight links on capture cards for Camera Link Medium, four coaxial lines into a frame grabber for CXP-12 ×1, adapters and ports for Ethernet.

Calculate for your case

The address carries the requirement, so nothing is retyped. Open the one-camera case or the four-camera case, and overwrite the fields with your own.

Two things the link does not do. It does not pick an interface, and the page has no manual profile selector: the page screens every profile and shows one recommendation with the expandable comparison described above. A single-profile filter exists one level down, as the interface parameter of the interface endpoint under /tools/api/v1/, which the link omits. The page also opens in manual mode: choosing a catalog camera in its model search switches the calculation to that camera's full frame, maximum frame rate, interface and pixel format, a different question.

Equipment: two 5 MP-class candidates, and one frame that matches without the frame rate

MV-CH050-90XM-C-NN and MV-CH050-10CM are the two records here with 5 MP-class geometry and a datasheet maximum frame rate above the 60 fps of the example: 2592 × 2160 pixels at up to 213 fps in Mono8 on CoaXPress with a DIN interface, and 2432 × 2048 pixels at up to 140 fps on Camera Link with an SDR interface (datasheet). The Camera Link record also lists Base, Medium, Full and 80-bit as its supported configuration modes, in a field of its own, separate from that maximum.

The two fields do not combine freely. At 140 fps with eight bits on the wire, 2432 × 2048 is 5.578 Gbit/s (calculated), and of those configurations only 80-bit at 6.80 Gbit/s covers it; at the 60 fps of this example the same frame is 2.391 Gbit/s (calculated), already above the 2.04 Gbit/s of Base. Clearing that arithmetic is a bandwidth result, not a passport mode. Neither camera has exactly the 2448 × 2048 frame of the example, so suitability needs the exact mode, pixel format and geometry confirmed on the variant, along with connector, cable, power and host board.

MV-CS050-10GM is the counter-example: exactly the 2448 × 2048 frame of this example on Gigabit Ethernet, but at a confirmed 24.2 fps (datasheet). Each figure is a full frame at a confirmed maximum, not a region-of-interest limit and not a claim about every pixel format.

Common mistakes

• The shortlist is taken for the decision, and a 20 m USB run is ordered on a passive cable that does not reach. Enter the run length with the stream and confirm a qualified option beyond the reference cable.
• The host-channel count is ordered as hardware: three 5GigE channels become three ports, and two streams share a channel that cannot hold them. Allocate the streams one at a time and buy against that sheet.
• Power is read off the interface name: taken for granted on an Ethernet camera, or ruled out for Camera Link where a PoCL-rated camera, board and cable would carry it. Confirm those part numbers while the routing is on paper.
• "No frame grabber needed" is read as "no host hardware needed", and four cameras end up on one shared USB controller. Count what each shared resource carries against its documented total.

When this rule breaks

A stream at or below the useful figure proves one thing: the requested image payload fits that profile's budget in our calculator. It does not prove zero dropped frames, host processing capacity, storage throughput or steady latency, and it does not clear transport as a cause. When a link that passed loses frames, commissioning walks the whole chain: the counters for incomplete and skipped images and for lost packets, the free buffers and underruns, the driver, the application's service time, the adapter's packet size, the camera's transmission delays, the switch and its uplinks, and the PCI Express and storage path (vendor documentation, Basler).

A profile is also not a camera. The list says which transports are worth checking, while the record of the model you intend to buy says which of them it implements, in which pixel format and at which frame rate.

Next step

Send us the resolution, frame rate, pixel format and camera count, the distance from each camera to the host, and whether the cameras take power from the cable. We run the stream against the current profiles, write the allocation of streams to ports and channels, and say where the plan needs a frame grabber, another adapter or its own power supply.

Related

How this material was prepared

Prepared with MVisionPro AI agents from stated sources and the calculation core; MVisionPro retains editorial responsibility. A physical test or human engineering review is claimed only when explicitly stated. Read the editorial method.

Editorial status: verified. Content updated 2026-09-21.