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Frequently Asked Questions

Plain answers on the hardware inside industrial and embedded systems: connectors, displays, processors, storage, networking, firmware and the standards they are built to. Pick a topic or search.

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Topics 12

MATERIALS · STAINLESS STEEL

What Is 316L Stainless Steel?

316L stainless steel is the low-carbon version of grade 316, an austenitic stainless steel with about 16–18% chromium, 10–14% nickel and 2–3% molybdenum. Carbon is held to 0.03% or less, so welded joints keep their corrosion resistance. It is widely used in food, pharmaceutical, marine and medical equipment, and in jewellery and watches.

6 MIN

STANDARDS · INGRESS PROTECTION

IP65 vs IP67: What Is the Difference?

IP65 and IP67 are both dust tight under IEC 60529. The difference is the water test: IP65 withstands water jets from a 6.3 mm nozzle, while IP67 survives temporary immersion to 1 m for 30 minutes. Neither rating includes the other, so equipment that faces both hosing and submersion is often dual-rated, such as IP65/IP67 or IP66/IP67.

5 MIN

STANDARDS · AUTOMOTIVE EMC

What Is ISO 7637-2?

ISO 7637-2 is the international standard for electrical transients conducted along the supply lines of road vehicles with 12 V or 24 V systems. It defines bench tests for the transients a device emits and for its immunity to standard test pulses, numbered 1, 2a, 2b, 3a and 3b, that copy switching events on a vehicle supply.

8 MIN

STANDARDS · RAIL

What Is EN 45545?

EN 45545 is the European standard series for fire protection on railway vehicles. Its seven parts cover vehicle design, fire barriers, electrical equipment, detection and flammable liquid systems, and Part 2 sets the fire behaviour of materials. Each vehicle is given a hazard level, HL1 to HL3, and each material must meet the requirement set for where it is used.

6 MIN

STANDARDS · CLEANROOMS

What Is an ISO 5 Cleanroom?

An ISO 5 cleanroom holds no more than 3,520 particles of 0.5 µm or larger in each cubic metre of air, the limit set by ISO 14644-1 and once called Class 100. It is used for aseptic filling, sterile compounding and semiconductor processes, and usually needs unidirectional, HEPA-filtered airflow across the work.

6 MIN

MARITIME · NAVIGATION

What Is ECDIS?

ECDIS, the Electronic Chart Display and Information System, is the type-approved navigation system that shows official electronic navigational charts with a ship’s position, heading, speed and planned route. Under SOLAS it can replace paper charts when it meets the IMO performance standard, is tested to IEC 61174 and has an approved back-up arrangement.

6 MIN

NETWORKING · SWITCHING

What Is a Layer 2 Switch?

A Layer 2 switch forwards Ethernet frames between devices using their MAC addresses, which belong to the data link layer (Layer 2) of the OSI model. It learns which device is on which port and sends each frame only where it needs to go. It connects devices within one network or VLAN; routing between networks needs Layer 3.

6 MIN

NETWORKING · SINGLE PAIR ETHERNET

What Is PoDL?

PoDL (Power over Data Lines) is the IEEE 802.3bu method of sending DC power over the single twisted pair of single pair Ethernet. Like PoE, it lets one cable carry data and power to a sensor or camera, but it uses one pair instead of two or four, with classes for 12 V, 24 V and 48 V systems.

6 MIN

NETWORKING · PROCESS AUTOMATION

What Is Ethernet-APL?

Ethernet-APL (Advanced Physical Layer) is a two-wire Ethernet physical layer for process plants. Built on 10BASE-T1L, it carries 10 Mb/s data and power over one twisted pair, with trunks up to 1,000 m and spurs up to 200 m, and supports intrinsic safety so field instruments in hazardous areas can connect to Ethernet directly.

6 MIN

NETWORKING · SINGLE PAIR ETHERNET

What Is 10BASE-T1L?

10BASE-T1L is long-reach single pair Ethernet: 10 Mb/s, full duplex, over one twisted pair for up to 1,000 m, defined in IEEE 802.3cg-2019. It brings native Ethernet to field devices that used 4–20 mA, HART or RS-485, can carry power on the same pair and is the physical layer beneath Ethernet-APL.

6 MIN

NETWORKING · SINGLE PAIR ETHERNET

What Is 10BASE-T1S?

10BASE-T1S is a 10 Mb/s Ethernet physical layer that runs over a single twisted pair for short distances, defined in IEEE 802.3cg-2019. Its distinctive feature is a multidrop bus: several devices can share one pair, taking turns through Physical Layer Collision Avoidance (PLCA). It brings native Ethernet to sensors and actuators where CAN or RS-485 sit today.

6 MIN

NETWORKING · TIMING

What Is a Grandmaster Clock?

A grandmaster clock is the reference clock at the top of a Precision Time Protocol (IEEE 1588) network. Every other clock in the PTP domain synchronises to it, directly or through switches. It is usually a dedicated appliance that takes time from GNSS satellites and keeps it with a stable oscillator if the signal is lost.

6 MIN

NETWORKING · TIMING

PTP vs NTP: What Is the Difference?

PTP (Precision Time Protocol, IEEE 1588) and NTP (Network Time Protocol, RFC 5905) both synchronise clocks over a network. NTP runs in software and typically holds a local network to around a millisecond. PTP timestamps packets in hardware and typically reaches sub-microsecond accuracy, but needs PTP-aware network cards and switches. Most sites run both.

6 MIN

MEMORY · PROCESSORS

LPDDR5 vs DDR5: What Is the Difference?

LPDDR5 and DDR5 are separate JEDEC memory standards. LPDDR5 is the low-power version: it is soldered next to the processor, uses narrow 16-bit channels and a very low I/O voltage, and suits compact, fanless and mobile designs. DDR5 comes on DIMMs and SO-DIMMs, so capacity can be larger and upgraded, and full ECC modules are available.

6 MIN

PROCESSORS · INTEL

Intel K vs KF: What Is the Difference?

The K in an Intel processor name means the multiplier is unlocked, so the chip can be overclocked on a motherboard that allows it. KF means unlocked with the integrated graphics disabled, so a separate graphics card is needed for any display. Otherwise a K and KF version of the same model share cores, clocks and power ratings.

6 MIN

PROCESSORS · EMBEDDED

Microcontroller vs Microprocessor: What Is the Difference?

A microcontroller (MCU) puts a CPU core, program flash, RAM and peripherals on one chip and runs a single firmware program, often without an operating system. A microprocessor (MPU) is a CPU that relies on external memory and storage and usually runs a full operating system such as Linux or Windows. Microcontrollers control hardware; microprocessors run applications.

6 MIN

PROCESSORS · ARM

What Is Arm Cortex?

Arm Cortex is the name of the CPU core designs Arm licenses to chipmakers. The cores come in three profiles: Cortex-A for applications processors that run Linux or Android, Cortex-R for real-time and safety-related control, and Cortex-M for microcontrollers. NXP, Rockchip, TI, NVIDIA and others build them into their own chips.

6 MIN

EDGE AI · JETSON SOFTWARE

What Is JetPack 6?

JetPack 6 is NVIDIA’s Jetson software release line for the Jetson Orin family. Built on Jetson Linux 36 with Ubuntu 22.04 and Linux kernel 5.15, it introduced an upgradeable compute stack, so CUDA and TensorRT can be updated without reflashing the board support package. It runs from 6.0 to 6.2, and 6.2 added the Super modes.

6 MIN

PROCESSORS · EMBEDDED DESIGN

What Is a Custom Carrier Board?

A custom carrier board is a baseboard designed for one product around a computer-on-module such as an NVIDIA Jetson or COM Express module. It carries only the connectors, power input and shape that product needs. It suits volume products and unusual I/O, at the cost of design work, an adapted board support package and compliance testing.

6 MIN

RELIABILITY · MAINTENANCE

What Is MTTR?

MTTR, usually short for mean time to repair, is the average time it takes to get a failed system working again, from the moment it fails until it is back in service. It is total repair downtime divided by the number of repairs. Together with MTBF it sets availability: the share of time a system is actually running.

6 MIN

THERMAL DESIGN · ENCLOSURES

What Is a Vortex Cooler?

A vortex cooler is an enclosure cooler that turns compressed air into a stream of cold air with a vortex tube, a device with no moving parts. Mounted on an electrical cabinet, it blows the cold air inside, vents warm air outside and keeps the enclosure slightly pressurised, which helps keep dust, oil mist and moisture out.

6 MIN

THERMAL DESIGN · ENCLOSURES

Enclosure Air Conditioner vs Heat Exchanger: What Is the Difference?

An enclosure air conditioner uses a refrigeration circuit, so it can hold the inside of a cabinet below the temperature of the surrounding air. An air-to-air heat exchanger only passes heat through a sealed core to cooler outside air, so the inside always stays warmer than the room. Both keep the enclosure sealed; the hottest outside air decides which works.

6 MIN

THERMAL DESIGN · RELIABILITY

What Is Junction Temperature?

Junction temperature (Tj) is the temperature of the active silicon inside a chip, where the transistors switch and the heat is produced. It is always higher than the package, the heatsink or the air around them. Every datasheet sets a maximum, Tj max: near it a processor throttles, and beyond it a device can be damaged or shut down.

6 MIN

STANDARDS · INDUSTRIAL CYBERSECURITY

What Is IEC 62443?

IEC 62443 is the international series of standards for the cybersecurity of industrial automation and control systems. Developed by ISA and the IEC, it sets requirements for asset owners, system integrators and product suppliers, and defines zones and conduits, seven foundational requirements and four security levels.

6 MIN