Monthly Archives: April 2017

What Influences Industrial Connectivity?

In the industry, any component coming in the path of delivering control signals or power to do useful work is termed industrial connectivity. For instance, components including relays, motor starters, terminal blocks, and connectors are all typical connectivity components.

Generic connectors can use low-cost material as they merely maintain electrical continuity. However, based on operating environments, connectors are differentiated into four categories: hermetic, military, industrial, and commercial. While hermetic connectors offer maximum exclusion of their inner structural materials from the elements, military and industrial connectors handle more rugged environments with hazards including thermal shock, vibration, corrosion, physical jarring, dust, and sand. Most commercial applications do not make such extreme demands of connectors, and therefore, atmospheric and temperature conditions are the least critical factors that affect the performance of commercial connectors. This allows designers to select from different connector materials.

Brass

This is a metal alloy made from copper and zinc, with manufacturers varying the proportions to create varying properties. Although brass has excellent conductivity, it cannot withstand abrasion from many cycles of insertion and withdrawal. It undergoes crystallization under repeated stress and loses flexibility as it ages. Suitable for non-critical and low-contact-force applications, it is easy to braze, weld, solder, and crimp brass.

Beryllium Copper

With excellent electrical, mechanical, and thermal properties, beryllium copper easily resists corrosion and wear. Among all copper-based spring alloys, beryllium copper is stronger and more resistant to fatigue, while able to withstand repeated insertion and withdrawal cycles. However, it is the most expensive among all basic contact materials.

Nickel-Silver Alloys

Not always requiring plating, nickel-silver alloys resist oxidation. While contacts made of nickel-silver alloys are susceptible to stress corrosion, the extent does not exceed that of brass.

Gold

Gold, a highly stable plating material, is an excellent conductor inferior only to silver and marginally so to copper. With the lowest contact resistance and providing the best protection from corrosion, manufacturers use hard gold plating for contacts experiencing frequent insertion/withdrawal cycles. For even greater frequency of cycling, gold impregnated with graphite offers only a slight increase of contact resistance.

Silver

A general-purpose plating metal for power contacts, silver has a poor shelf life and tarnishes when exposed to the atmosphere. Although this increases the contact resistance, the oxide coating does not affect contacts carrying higher currents.

Nickel

With good corrosion resistance, nickel offers low contact resistance and fair conductivity. Therefore, it is used as an undercoat to prevent migration of silver through gold in high-temperature environments. Although it has good wear resistance, nickel may crack during crimping unless properly plated onto the base material.

Rhodium

Manufacturers use rhodium for contacts that need exceptional wear qualities. Although conductivity of rhodium is lower than that of gold or silver, the higher resistance is acceptable for thin coatings.

Tin

Providing good conductivity and excellent solderability, tin offers a low-cost finish and poor wipe resistance. This makes it the most suitable for connections requiring only very few mating cycles. Tin, not being a noble metal, will corrodes easily.

Gold-Over-Nickel

This is a widely used plating combination as it offers the surface qualities of gold, while minimizing the amount of gold required. The hard under-plating of nickel prevents migration of the base metal.

Diamondoids Make Three Atoms Wide Wires

At the SLAC National Accelerator Laboratory of the Department of Energy, and the Stanford University, scientists have discovered a new method of using diamondoids. These extremely tiny bits of diamonds, these diamondoids can be used to assemble atoms into the thinnest possible electrical wires—only three atoms wide.

The diamondoids do this by grabbing different types of atoms and bringing them together as is done in LEGO units. The scientists are of the opinion this new technique has the potential of creating tiny wires suitable for a wide range of applications. This could include fabrics for generating electricity, superconducting materials for conducting electricity without any loss, and optoelectronic devices employing both light and electricity. The scientists have reported their findings in Nature Materials.

According to Hao Yan, a lead author of the paper and a postdoctoral researcher at Stanford, the process self-assembles tiny, conductive wires of the smallest possible size. The process involves simply dumping the ingredients together, with the results coming in only half an hour.

The researchers have made an animation to show the molecular building blocks joining the tip of the growing nanowire. In each block, there is a diamondoid, attached to sulfur and copper atoms. Just as LEGO blocks do, the diamondoids only fit together in specific ways that their shape and size dictate. While the insulating diamondoids form an outer shell, the sulfur and copper atoms make up a conductive wire in the center.

Although several methods exist for self-assembly of materials, the method with diamondoids is the first one to make a nanowire with a solid, crystalline core. According to a co-author of the study Nicholas Melosh, the core also has good electronic properties.

The semiconducting core of the needle-like wires—a combination of copper and sulfur, known as chalcogenide—is surrounded by an insulating shell formed by diamondoids.

According to Melosh, this miniscule size is very important. In reality, the material exists in only one or two dimensions—as wires or sheets of atomic-scale dots. At these dimensions, the material has very different properties, extraordinarily different compared to those of the same material when made in bulk. With the new method, researchers were able to assemble the materials with atomic precision and control.

The scientists used the diamondoids as assembly tools, as these are tiny, with interlocking cages of carbon and hydrogen. The SLAC laboratory extracted and separated the diamondoids by size and geometry from petroleum fluids, where the diamondoids occur naturally. Melosh and professor Zhi-Xun Shen from SLAC/Stanford are leading a SIMES research program over the past decade. They have found several potential uses for the diamondoids. This ranges from making tiny electronic gadgets to improving electron microscope images.

The research team found that tiny diamonds attract each other strongly—through van der Waals forces—a fact they exploited. Because of this attraction, the microscopic diamondoids can clump together much the same way as sugar crystals do, this being the only reason they are visible to the naked eye. The scientists started with the smallest possible dimensions of the diamondoids. They used single cages containing just 10 carbon atoms, to each of which they attached a sulfur atom. When the sulfur atom bonded with a single copper ion, it created the basic building block for a nanowire.

RS485 Relay Output Module for the Raspberry Pi

Although many consider the RS485 relay output module as an archaic protocol, it is still important to the industry. The RS485 protocol allows up to 32 devices to communicate through the same data line over a cable length of up to 4000 feet with a maximum data rate of 10 Mbps. Not many other protocols can equal those numbers.

The single board computer, the Raspberry Pi (RBPi) is increasingly finding its way into more and more industrial applications. However, the limiting factor for most compatible relay modules is the number of contacts available, which are either too few, or limited by the GPIO pins used.

The RS485 relay interface overcomes this limiting factor. Modules such as the Pi-SPi-RS485 and VP-EC-8K0 support the Modbus protocol. That offers the industrial user up to 253 modules at eight relays per module, theoretically making it possible to use 2,024 relays from one interface. Practically, there are two limitations.

According to the hardware protocol, the RS485 relay can support up to 32 unit loads, before a repeater/amplifier becomes necessary for the next batch of loads. Popular modules use the Texas Instruments RS485 drivers such as the SN65HVD72DR half-duplex IC, which according to the TI data sheet, allow only up to 200 unit loads.

In addition, the hardware protocol of the RS485 relay output module specifies the maximum distance between the extreme ends of the RS485 transmission line cannot exceed 4000 feet. For greater distances, a repeater/amplifier becomes necessary.

Therefore, for any industrial application requiring serious outputs such as few hundreds of easily configurable relays, each with 10 A SPDT contacts with MOV protection, where the distances are within 4000 feet between all modules, the RS485 modules for the RBPi are a perfect fit. Some modules are field ready as they have an optional DIN rail enclosure.

RS485

RS485 is an industrial standard for transmitting serial data via a hard-wired cable—EIA/TIA-485 defines the system. RS485 offers the ability of multi-drop cabling with data speeds of up to 10 Mbps over 50 feet, and slower communication speeds of 100 kbps for up to 4000 feet. Industrial applications such as data acquisition widely use the RS485 protocol.

Simple networks often use RS485 links, connected in 2- or 4-wire mode. A typical application may have several addressable devices linked to a single controller, PC, or SBC such as the RBPi. This typically uses a single line for communication.

Using simple interface converters, linking systems using the RS485 and RS232 protocols is possible. This may include optical isolation between the two circuits. It is also possible to incorporate surge suppression for any electrical spikes that the communication line may pick up.

RS485 makes it easy to construct a multi-point data network for communication. According to the protocol, you can have 32 nodes capable of both transmitting and receiving. Furthermore, you can easily extend this capability further by using automatic repeaters and using high-impedance drivers/receivers. That means hundreds of nodes can exist on a network, extending the common mode range for both drivers and receivers with tri-state and power off modes for power saving.

Importance of Resolution in Thermal Imaging

Thermal imaging technologies have long been associated with a range of applications and industries for discovering abnormalities and weak points quickly and efficiently. These technologies are ideal for production monitoring and other applications as materials and components undergo non-destructive testing under operating conditions. That allows discovery of the problem before a breakdown can occur or a fire risk can develop.

For instance, thermal imaging allows contractors in a building, facilities maintenance, HVAC, and in electrical industries to visualize situations they are facing—they know where to start with as job, and it saves them time and effort. That means they can improve their efficiency, ultimately providing faster service to customers.

Resolution of the image is very important in thermal imaging. The details matter when using thermography for detecting leakages, cold bridges, mold, or overheated components. Most such elements are visible only when the resolution of the image is 160×120 pixels or more. As the technology uses each pixel as a measurement point, measuring accuracy improves with higher resolution. Accurate measurements are necessary for detecting irregularities earlier, avoiding unnecessary damages for you and the customer.

Using a camera with exceptional resolution has additional advantages. It is not necessary to be near the abnormality when capturing its thermal image, thereby leaving the image quality unaffected. Low-resolution thermal images can be unclear, and may not offer true or accurate readings. Therefore, industrial thermal imaging practically starts from a resolution of 160×120 pixels, as this is the minimum to offer true value.

Several industries use thermal imaging. However, for the best application of this technology, it is necessary to use a robust, quality camera. Here are some examples where thermal imaging is a huge advantage:

Heating Installations

A thermal camera can make visible a leaking pipe hidden under plaster, which is impossible to locate with the naked eye. Similarly, it is easy to visualize under the floor heating courses, and check the performance of a radiator non-intrusively. In addition to the resolution, it is necessary to have a thermal sensitivity of at least 100 mK.

Inspection of Switching Cabinets

A temperature rise usually precedes a malfunction in a switching cabinet. Using a high-resolution thermal camera, not only can one measure this rise, but also visualize the location of the heat source. As all this happens without contact, it is impossible to miss an overheated contactor, an insufficiently tightened clamp, or an overloaded cable.

Discovering Defects in Buildings

Detecting sealing and insulation defects or discovering and analyzing cold bridges in buildings can be done far more quickly and accurately using thermal imaging than with any other tool. Apart from initiating preventive measure timely, this ensures building quality, while impressing the customer with the visual representation of the quality of workmanship.

Identifying Dangers from Mold

With high-quality thermal imaging, it is easy to calculate the value of humidity at each measuring point. The calculation depends on the externally measured ambient temperature, the humidity of air, and the determined surface temperature. The imager has a humidity palette, which represents the different risk zones with the principle of traffic lights—Green for no risk, Amber for caution, and Red for danger.

Tinker Board: Raspberry Pi Competitor from ASUS

The community of single board computer users is passionate and the DIY enthusiasts are growing daily. While they are infatuated with the amazingly tiny package called the Raspberry Pi (RBPi), they are constantly clamoring for more performance and connectivity features. This demand has produced several competitors to the RBPi, and the tech giant, ASUS Computers is now providing one in the form of a Tinker Board.

The ASUS Computers product is a mini-PC based on the ARM core, and its actual model number is the ASUS 90MB0QY1-M0EAY0. However, it is easier to remember it as the Tinker Board. The smart name from ASUS for the product is the exact demographic of its intention, offering a tiny, all-in-one product for makers and tinkerers, to use in media servers, fun projects, and embedded applications. For instance, the Tinker Board allows one to build a personal NES Mini alternative.

Although a 64-bit ARM Cortex-A47 quad-core processor, the Broadcom BCM2837, powers the RBPi3 at 1.2 GHz, a 32-bit ARM Cortex-A17, the quad-core Rockchip RK3288 processor powers the Tinker Board, operating at 1.8 GHz. ASUS claims the Tinker Board is almost twice as fast as the RBPi3 model B. Additionally, against the 1 GB RAM configuration of the RBPi3, the Tinker Board offers 2 GB of RAM.

The Tinker Board has other advantages as well. The hardware includes the complete H.264 4K video decode capability, supported by a far stronger graphics performance from the ARM Mali-T764 with a graphics core of the Rockchip RK3288. The audio capabilities are also better with the Asus minicomputer offering audio sample rates at 192K/24-bit, while the RBPi3 offers only 48K/16-bit, which necessitates an add-on board for HD audio from the RBPi3.

The integrated, Gigabit Ethernet port at full speed on the Tinker Board gives it a substantial boost over the 100 Mb LAN on the RBPi3. Similar to that available on the RBPi3B, the Tinker Board also has an 802.11b/g/n Wi-Fi and Bluetooth 4 capability. In addition, it has support for SDIO 3.0, and offers swappable antennas for the built-in 802.11 b/g/n Wi-Fi module.

Similar to the RBPi3B, the Tinker Board also supports the Debian Linux (modified by ASUS) operating system and KODI, with its slick media streaming interface. Similar to the RBPi, the Tinker Board also comes with no on-board storage, and you have to use a micro SD card. However, the additional capabilities on the Tinker Board make it about twice as expensive as compared to the market price of the RBPi3B.

Physically, both single board computers are of the same size, with mounting holes in the same position. Obviously, ASUS wants the Tinker Board to be a drop-in replacement for the RBPi3. The same configuration of the GPIO pins for both boards lends further support to this credence.

The RBPi concept has spawned a whole new era of tiny computer devices, selling in several schools, colleges, and universities. Many other device manufacturers have since piled on and released their own version of the credit-card sized powerhouse.

In this chaotic, crowded environment, the specifications of the Tinker Board, although not ground breaking, could play nicely in the existing RBPi-based projects.