Semiconductor Testing

Automated test equipment (ATE) is computer-controlled test and measurement equipment that allows for testing with minimal human interaction. The tested devices are referred to as a device under test (DUT). The advantages of this kind of testing include reducing testing time, repeatability, and cost efficiency in high volume. The chief disadvantages are the upfront costs of programming and setup.
Automated test equipment can test printed circuit boards, interconnections, and verifications. They are commonly used in wireless communication and radar. Simple ATEs include volt-ohm meters that measure resistance and voltages in PCs; complex ATE systems have several mechanisms that automatically run high-level electronic diagnostics.
ATE is used to quickly confirm whether a DUT works and to find defects. When the first out-of-tolerance value is detected, the testing stops and the device fails.

Semiconductor Testing

For ATEs that test semiconductors, the architecture consists of a master controller (a computer) that synchronizes one or more sources and capture instruments, such as an industrial PC or mass interconnect. The DUT is physically connected to the ATE by a machine called a handler, or prober, and through a customized Interface Test Adapter (ITA) that adapts the ATE's resources to the DUT.
When testing packaged parts or directly on the silicon wafer, a handler is used to place the device on a customized interface board and silicon wafers are tested directly with high precision probes.

Test Types

Logic Testing

Logic test systems are designed to test microprocessors, gate arrays, ASICs and other logic devices.
Linear or mixed signal equipment tests components such as analog-to-digital converters (ADCs), digital-to-analog converters (DACs), comparators, track-and-hold amplifiers, and video products. These components incorporate features such as, audio interfaces, signal processing functions, and high-speed transceivers.
Passive component ATEs test passive components including capacitors, resistors, inductors, etc. Typically, testing is done by the application of a test current.
Discrete ATEs test active components including transistors, diodes, MOSFETs, regulators, TRIACS, Zeners, SCRs, and JFETs.

Printed Circuit Board Testing

Printed circuit board testers include manufacturing defect analyzers, in-circuit testers, and functional analyzers.
Automated Test Equipment imageManufacturing defect analyzers (MDAs) detect manufacturing defects, such as shorts and missing components, but can't test digital ICs as they test with the DUT powered down (cold). As a result, they assume the ICs are functional. MDAs are much less expensive than other test options and are also referred to as analog circuit testers.
In-circuit analyzers test components that are part of a board assembly. The components under test are "in a circuit." The DUT is powered up (hot). In-circuit testers are very powerful but are limited due to the high density of tracks and components in most current designs. The pins for contact must be placed very accurately in order to make good contact. They are also referred to as digital circuit testers or ICT.
A functional test simulates an operating environment and tests a board against its functional specification. Functional automatic test equipment (FATE) unpopular due to the equipment not being able to keep up with the increasing speed of boards. This causes a lag between the board under test and the manufacturing process. There are several types of functional test equipment and they may also be referred to as emulators.

Interconnection and Verification Testing

Test types for interconnection and verification include cable and harness testers and bare-board testers.
Cable and harness testers are used to detect opens (missing connections), shorts (open connections) and miswires (wrong pins) on cable harnesses, distribution panels, wiring looms, flexible circuits, and membrane switch panels with commonly-used connector configurations. Other tests performed by automated test equipment include resistance and hipot tests.
Bare board automated test equipment is used to detect the completeness of a PCB circuit before assembly and wave solder.

LabVIEW Improvements

LabVIEW passed its 30 year anniversary in 2016,  and six months ago, National Instruments, has launched a considerably updated version of LabVIEW - its Next Generation LabVIEW NXG 1.0.
LabVIEW NXG is a totally reworked version of LabVIEW and this enables it to offer a considerably improved level of performance. By adopting an approach where LabVIEW has been started again from the ground up, LabVIEW NXG enables users to see significant improvements in performance as a result of the new code.
LabVIEW NXG offers some significant definitive improvements over the previous implementation of LabVIEW:

• Plug & Play: a lot of work has gone into enabling LabVIEW NXG to provide easy set-up of hardware connections. It has true plug and play functionality.
• IDE: The LabVIEW NXG environment has been totally overhauled to take elements of popular commercial software and replicate the attributes of the environment to make it more intuitive.
• Tutorials: To facilitate the speedy uptake of newcomers to LabVIEW, the new LabVIEW NXG has inbuilt walk-throughs and other integrated learning facilities. This has been shown to greatly speed up the time which it takes for newcomers to be able to proficiently programme in LabVIEW. It is even possible to undertake a number of standard tasks without “hitting the code.”

National Instruments will be running both the traditional LabVIEW, i.e. LabVIEW 2017 which has also been launched alongside the new next-generation LabVIEW NXG, but ultimately when total compatibility has been established the two will converge enabling users to benefit from the new streamlined core.
Users of LabVIEW will be given access to both LabVIEW 2017 and later versions as well as LabVIEW NXG. In this way, they can make the choice of which version suits their application best.
National Instruments spokespeople stressed that the traditional development line of LabVIEW will continue to be maintained so that the large investment in software and applications that users have is not at risk. However, drivers and many other areas are already compatible with both lines.

“Thirty years ago, we released the original version of LabVIEW, designed to help engineers automate their measurement systems without having to learn the esoterica of traditional programming languages. LabVIEW was the ‘nonprogramming’ way to automate a measurement system,” said Jeff Kodosky, NI co-founder and business and technology fellow, known as the ‘Father of LabVIEW.’
“For a long time, we focused on making additional things possible with LabVIEW, rather than furthering the goal of helping engineers automate measurements quickly and easily. Now we are squarely addressing this with the introduction of LabVIEW NXG, which we designed from the ground up to embrace a streamlined workflow. Common applications can use a simple configuration-based approach, while more complex applications can use the full open-ended graphical programming capability of the LabVIEW language, G.”

9 Things to Consider When Choosing Automated Test Equipment

Automated test equipment (ATE) have the ability to reduce the costs of testing and make sure that lab teams can focus on other, more important tasks. With ATE, productivity, and efficiency is boosted to a maximum level due to cutting out the unnecessary tasks and daily activities.
However, you should not just cash out and invest in automated test equipment, there are elements that factors that are important to find the system that suits you best. Our team at ReadyDAQ has prepared 12 things you should consider before choosing automated test equipment.

1. Endurance and Compactness

One of the most important things is that the ATE system your company picks is designed for optimal performance over the long-term. Take a careful look at connections and components and make a conclusion whether they will survive over repeated use.Many lab teams are often struggling to find large areas for their testing operations. The automated test equipment should also be compact.

2. Customer Experience

Are other customers satisfied the support and other things they went through? Does the company you bought ATE from provide full support? You don't have to be the expert in automated test equipment, but they do. And their skills and expertise have to be available to you for when you need it. Customer support and the overall customer experience is a huge factor!

3. Scalability and Compatibility

One purchase does not have to be final. It often isn't You should check whether the equipment you ordered can be expanded or scaled over time. Your needs might change and you want ATE to adapt to your needs.
When compatibility comes to mind, we want to make sure that the equipment is built following all industry standards. Cross-compatibility is often important in situations where we no longer need or have lost the access to certain products. Better safe than sorry.

4. Comprehensive

Think of all the elements needed for testing. Even better, make a list. Does the equipment you have in mind cover ALL required elements? Don't forget about power and signaling, are they included too?

5. High Test Coverage and Diagnostics 

The ATE system has to be able to provide full coverage and give insights on all components of the processed product. This can help decrease the number of possible errors and failures later on.
How about diagnostics? Does the testing system provide robust diagnostic tools to make sure the obtained results are reliable and true?

6. Cost per Test

How much does a single test cost? You have to think and plan long-term, so a single test cost can help you calculate and make an assumption whether the system provides real value for the money invested.

7. Testimonials and Warranty 

Are other customers satisfied? Can the company direct you to testimonials from previous customers? What do their previous customers have to say about the systems and their performance?
Also, you don't want to be left hanging in case the systems starts malfunctioning or simply stops working. Does the ATE system come with a comprehensive warranty? Make sure you’re protected against damages that might happen in testing and see that the warranty covers that too.

8. Manufacturer Reputation

When did you first hear about the company? How? Did someone (besides them) say anything good about them? Is the company known for the high quality of their equipment? Discuss their past projects and learn more about the value their products provide.

9. Intuitive Performance

At first sight, is the system easy to use or way too complicated that it would require weeks of training for everyone in the lab? Does it offer intuitive performance within the testing procedure? Your team should be able to begin testing without having to go over every point in the technical manual in pinpoint detail.
Our team at ReadyDAQ is here to help you select the perfect automated test equipment for your lab.

What is RS-232, what is RS-422, and what is RS-485?

RS-232, RS-422 and RS-485 are serial connections which can be found in various consumer electronics devices. Namely, RS-232 (ANSI/EIA-232 Standard) is the serial connection which can be historically found on IBM-compatible PCs. It is employed in many different scenarios and for many purposes, such as connecting a mouse, a printer, or a modem, as well as connecting different industrial instrumentation. Due to improvements in line drivers and cables, applications often expand the performance of RS-232 beyond the distance and speed limits which are listed in the standard. RS-232 is restricted to point-to-point connections between PC serial ports and various other devices. RS-232 hardware can be employed for serial communication up to distances of 50 feet.
On the other hand, RS-422 (EIA RS-422-A Standard) is the serial connection which can be historically found on Apple Macintosh computers. RS-422 employs a differential electrical signal, as opposed to unbalanced signals referenced to ground with the RS-232. Differential transmission employs two lines each for transmitting and receiving signals which lead to greater immunity to noise and the signal can travel longer distances as compared to the RS-232. These advantages make RS-422 a better option to consider for industrial applications.
Finally, RS-485 (EIA-485 Standard) is an improvement over RS-422, because it increases the number of devices from 10 to 32 and defines the electrical features necessary to safeguard adequate signal voltages under maximum capacity. With this enhanced multi-drop capability, one is able to create networks of devices connected to a single RS-485 serial port. The noise immunity and multi-drop capability make RS-485 the serial connection of choice in industrial applications requiring many distributed devices networked to a PC or other controller for data collection, HMI, or other operations. RS-485 is a superset of RS-422; therefore, all RS-422 devices can be controlled by RS-485. RS-485 hardware can be employed for serial communication with up to 4000 feet of cable network.

I²C and SPI

Nowadays, at the low end of the transmission protocols, I²C (for ‘Inter-Integrated Circuit’, protocol) and SPI (for ‘Serial Peripheral Interface’) are to be found. Both protocols are well-suited for transmissions betwixt unified circuits, for slow transmission with onboard components. At the essence of these two popular protocols two major companies are found – Philips for I²C and Motorola for SPI – and two diverse histories about why, when and how the protocols were generated.
The I²C bus was developed in 1982; its authentic purpose was to supply an effortless way to link a CPU to peripherals chips in a TV set. Peripheral instruments in embedded systems are frequently connected to the microcontroller as memory-mapped I/O mechanisms. One straightforward way to do this is connecting the components to the microcontroller parallel address and data busses. This results in countless wiring on the PCB (printed circuit board) and supplementary ‘glue logic’ to decode the address bus on which all the peripherals are connected. To reserve microcontroller pins, further logic and make the PCBs simpler, in order words, to lower the expenditure.
SPI is a single-master communication protocol. This means that one fundamental device initiates all the communications with the servants.

About Temperature Data Loggers

A data logger is, simply put, an electronic device which records and stores data. There are various ways data devices, or data loggers, tools designed for recording or monitoring processes and different parameters, acquire data. These data loggers have become a revolutionary solution for logging vast amounts of data and are nowadays symbolized by a vast array of devices, from small, handheld ones to complex systems. For example, a data logger device can be applied to automobile and other vehicle control, then the acquisition of machine or engine data and monitoring of conditions present in a machine. Multichannel systems which track vibration, force detection and various measurements in turbines and generators can all be found. The findings are later presented as charts, graphs and diagrams.

Temperature data logger

Temperature data loggers, also called temperature monitoring devices, can be found with ease, and they offer a variety of solutions to adapt to any temperature measurement scenario. Data loggers which measure atmospheric temperature almost always have a built-in sensor which is then employed to measure surrounding temperatures in rooms, fridges or other enclosed spaces. Needless to say, these instruments are capable of autonomous work, that is, they record temperatures over a defined period, without the need of a person meddling with it.

There are many various constructions available for data logging devices. Most of these devices have internal measuring sensors or can be linked to external sources. Also, most of these devices can be connected to via cord, RFID or a wireless system for data retrieval purposes, calibration or set up; many can also be set up and controlled via a personal computer or a smartphone. These devices are usually small, battery-powered, portable, equipped with internal memory for data storage, a connection for data retrieval of choice and sensors.

RS-232 and RS-485 Serial Communication Protocols

The RS232/485 port consecutively sends and receives bytes filled with information one bit at a time. Although the serial method is somewhat slower than parallel communication, which allows the transmission of an entire byte at once, it is far simpler and can be employed over longer distances because power consumption is lower than that of parallel one. As an example, the IEEE 488 standard for parallel communication requires that the cabling between equipment can be no more than 20 meters total, with no more than 2 meters between any two connected devices. On the other hand, RS232/485 cabling is possible to be extended 1200 meters or greater.
Typically, RS232/485 is employed to transmit American Standard Code for Information Interchange (ASCII) data. Although National Instruments serial hardware is able to transmit 7-bit as well as 8-bit data packages, many applications use 7-bit data. Seven-bit ASCII can represent the English alphabet, decimal numbers, and common punctuation marks. It is a standard protocol that virtually all hardware and software are able to comprehend. Serial communication is completed employing three transmission lines: (1) ground, (2) transmit, and (3) receive. Due to the fact that RS232/485 communication is asynchronous, the serial port is able to send and receive data on one line while also sending and receiving data on another. Other lines are also available, but are not required nor are they employed. The crucial serial characteristics are baud rate, data bits, stop bits, and parity. These parameters must match to allow communication between a serial device and a serial port on a computer.
The RS-232 port, or ANSI/EIA-232 port, is the serial connection which one is able to come across on most PCs. It is used for many purposes, such as connecting a mouse, a printer, or a modem, as well as other various industrial instrumentation. The RS-232 protocol is able to withstand only one device connected to each port. The RS485 (EIA-485 Standard) protocol is able to have 32 devices connected to each port. With this enhanced multidrop capability, one can create networks of devices connected to a single RS-485 serial port. Noise immunity and multidrop capability make RS-485 the serial connection of choice in industrial applications which are in need of many distributed instruments and peripherals connected to a PC or other controller for data collection.

Uses for Data Loggers

There are numerous uses for autonomous data loggers, one of which being environmental monitoring: they can be taken to various locations that cannot be accessed easily with bulky temperature monitoring equipment such as mountains, deserts, jungles, mines, caves and other similar places. Data loggers, especially portable ones, can also be used in industrial and scientific surroundings – in factories and laboratories where temperature monitoring is highly wanted.

 

Another use for temperature data loggers is monitoring sensitive shipments and products, primarily fresh and prepared foods and other consumables, pharmaceuticals, organs ready for transplant and various chemicals which react to elevated temperatures and need to be kept in order. Exposing the aforementioned items to temperatures outside their designated ranges for a certain period of time can result in them being unusable. Therefore, portable data loggers are placed inside insulated containers or directly attached to products and items so as to monitor the temperature of the product being shipped. Also, the placement of data loggers and sensors is critical to the perseverance of the product: several studies have confirmed that temperatures inside a shipping container (an insulated box, a refrigerator truck or a refrigerated container) rely heavily on the proximity of the container to exterior walls and roof and to the location in regard to them.

 

Modern data loggers also come equipped with the ability to measure temperature in real time. This information can then be used to check whether the product has been exposed to temperatures higher than prescribed for too long. Analyzing these scenarios of high temperature exposure, the outcomes may be that shelf life of products has been reduced and therefore they need to be sold at a faster pace, perhaps the cooling equipment has failed during the shipping of a product but persons cannot pick up the slight difference in temperatures, or the shipment has gone bad and is unusable because of critical oscillations of temperature.

 

All of this data coming from monitoring temperature can prove to be extremely useful as to reduce costs, prolong shelf life and avoid any damage to the precious goods so that they can be usable and in top condition upon arrival.

I²C vs SPI - comparison

Bus topology / routing / resources

I²C needs two lines, while SPI officially defines at least four signals or more if more servants are added. Some informal SPI alternatives only need three wires, that is an SCLK, SS and a bi-directional MISO/MOSI line. Nevertheless, this exercise would require one SS line per servant. SPI lacks further work, logic and/or pins if a multi-master engineering must be built on SPI. The singular problem I²C when building a system is a finite machine address space on 7 bits, overwhelmed with the 10-bits enlargement.
From this point of view, I²C is a clear winner over SPI in sparing pins, board routing and how effortless it is to build an I²C network.

Throughput / Speed

If data must be relocated at ‘high speed’, SPI is apparently the protocol of choice, over I²C. SPI is full-duplex, and I²C is not. SPI does not determine any speed limit. Exercise often go over 10 Mbps. I²C is limited to 1Mbps in Fast Mode+ and to 3.4 Mbps in High-Speed Mode. This last one requires particular I/O buffers, not regularly easily available.

Elegance

It is usually said that I²C is much more elegant than SPI and that this last one is a very ‘rough’ protocol. People tend to think the two codes are equally elegant and comparable on robustness.
I²C is elegant for it offers very advanced appearances, such as automatic multi-master clashes handling and built-in addressing management, on a very light foundation. It can be very complex, nonetheless and somewhat lacks performance.
SPI, on the other hand, is quite easy to comprehend and to implement and offers a great deal of flexibility for extensions and alternatives. The disparity is where the elegance of SPI lies. SPI should be considered as a good platform for building custom protocol piles for transmission between ICs. Thus, in accordance with to the engineer’s need, using SPI may need more work but offers raised data transfer performance and almost total freedom.
Both SPI and I2C offer favourable support for connection with low-speed machines, but SPI is improved suited to applications in which devices assign data streams, while I²C is improved at multi master ‘register access’ application.

How to keep multicloud complexity under control

Using multiple cloud providers provides needed flexibility, but it also multiplies the work and risk of getting out of sync
“Multicloud” means that you use multiple public cloud providers, such as Google and Amazon Web Services, AWS and Microsoft, or all three—you get the idea. Although this seems to provide the best flexibility, there are trade-offs to consider.
The drawbacks I see at enterprise clients relate to added complexity. Dealing with multiple cloud providers does give you a choice of storage and compute solutions, but you must still deal with two or more clouds, two or more companies, two or more security systems … basically, two or more ways of doing anything. It quickly can get confusing.
For example, one client confused security systems and thus inadvertently left portions of its database open to attack. It’s like locking the back door of your house but leaving the front door wide open. In another case, storage was allocated on two clouds at once, when only one was needed. The client did not find out until a very large bill arrived at the end of the month.
Part of the problem is that public cloud providers are not built to work together. Although they won’t push back if you want to use public clouds other than their own, they don’t actively support this usage pattern. Therefore, you must come up with your own approaches, management technology, and cost accounting.
The good news is that there are ways to reduce the multicloud burden.
For one, managed services providers (MSPs) can manage your multicloud deployments for you. They provide gateways to public clouds and out-of-the-box solutions for management, cost accounting, governance, and security. They will also be happy to take your money to host your applications, as well as provide access to public cloud services.
If you lean more toward the DIY approach, you can use cloud management platforms (CMPs). These place a layer of abstraction between you and the complexity of managing multiple public clouds. As a result, you use a single mechanism to provision storage and compute, as well as for security and management no matter how many clouds you are using.
I remain a fan of the multicloud approach. But you’ll get its best advantage if you understand the added complexity up front and the ways to reduce it.

6 Steps on How to Learn or Teach LabVIEW OOP - Part 2

Step 4 – Practice!
This stage is harder than the last. You need to make sure:
Each child class should exactly reflect the abstract methods. If your calling code ever cares which sub-class it is calling by using strange parameters or converting the type then you are violating LSP – the Liskov substitution principle – The L of solid.
Each child class should have something relevant to do in the abstract classes. If it has methods that make no sense this is a violation of the interface segregation principle.
Step 5 – Finish SOLID
Read about the open-closed principle and the dependency inversion principle and try it in a couple of sections of code.
Open-closed basically means that you leave interfaces (abstract classes in LabVIEW). Then you can change the behavior by creating a new child class (open for extension) without have to modify the original code (closed to modification). This goes well with the dependency inversion principle. This says that higher level classes should depend only on interfaces (again abstract classes). This means the lower level code implements these classes and so the high-level code can call the lower level code without a direct dependency.
This goes well with the dependency inversion principle. This says that higher level classes should depend only on interfaces (again abstract classes). This means the lower level code implements these classes and so the high-level code can call the lower level code without a direct dependency. This can help in places where coupling is difficult to design out.
I leave these principles to the end because I think they are the easiest to write difficult to read code. I’m still trying to find a balance with these – following them wholeheartedly creates lots of indirection which can affect readability. I also think we don’t get as much benefit in LabVIEW with these since we don’t tend to package code within projects in the same way as other languages. (this maybe a good topic for another post!)
Step 6 – Learn some design patterns
This was obviously part of the point of this article. When I came back to design patterns after understanding design better and the SOLID principles it allowed me to look at the patterns in a different way. I could relate them to the principles and I understood what problems they solved.
For example, the command pattern (where you effectively have a QMH which takes message classes) is a perfect example of a solution to meet the open-closed principle for an entire process. You can extend the message handler by adding support for new message types by creating new message classes instead of modifying the original code. This is how the actor framework works and has allowed the developers to create a framework where they have a reliable implementation of control of the actors but you can still add messages to define the functionality.
Once you understand why these design patterns exist you can then apply some critical thinking about why and when to use them. I personally dislike the command pattern in LabVIEW because I don’t think the additional overhead of a large number of message classes is worth the benefit of being able to add messages to a QMH without changing the original code.
I think this will help you to use them more effectively and are less likely to end up with a spaghetti of design patterns thrown together because that is what everyone was talking about.
Urmm… so what do I do?
So I know this doesn’t have the information you need to actually do this so much as set out a program. Actually, all the steps still follow the NI course on OOP so you could simply self-pace this for general learning material.

Getting Started with CompactRIO - Performing Basic Control

 

The National Instruments Compact

An advanced embedded data and control acquisition system created for applications that require high performance and reliability equals RIO programmable automation controller. The system has open, embedded architecture, extreme ruggedness, small size, and flexibility, that engineers and embedded planners can use with COTS hardware to instantly build systems that are custom embedded. NI CompactRIO is powered by National Instruments LabVIEW FPGA and LabVIEW Real-Time technologies, it gives engineers the ability to program, design, and customize the CompactRIO embedded system with handy graphical programming tools.

This controller fuses a high-performance FPGA, an embedded real-time processor, and hot-swappable I/O modules. Every I/O module that grants low-level customization of timing and I/O signal processing is directly connected to the FPGA. The embedded real-time processor and the FPGA are connected via a high-speed PCI bus. A low-cost architecture with direct access to low-level hardware assets is shown by this. LabVIEW consists of built-in data transfer mechanisms that pass data from both the FPGA and the I/O modules to the FPGA to the embedded processor for real-time post-processing, analysis, data logging, or communication to a networked host CPU.

FPGA

A reconfigurable, high-performance chip that engineers may program with LabVIEW FPGA tools is the installed FPGA. FPGA designers were compelled to learn and use complex design languages such as VHDL to program FPGAs, and now, any scientist or engineer can adapt graphical LabVIEW tools to personalize and program FPGAs. One can implement custom triggering, timing, control, synchronization, and signal processing for an analog and digital I/O by using the FPGA hardware installed in CompactRIO.

C Series I/O Modules

A diversity of I/O types are accessible including current, voltage, thermocouple, accelerometer, RTD, and strain gauge inputs; 12, 24, and 48 V industrial digital I/O; up to ±60 V simultaneous sampling analogue I/O; 5 V/TTL digital I/O; pulse generation; counter/timers; and high voltage/current relays. People can frequently connect wires directly from the C Series modules to their actuators and sensors, for the modules contain built-in signal conditioning for extended voltage ranges or industrial signal samples.

Weight and Size

Demanding design requirements in many embedded applications are size, weight, and I/O channel density. A four-slot reconfigurable installed system weighs just 1.58 kg (3.47 lb) and measures 179.6 by 88.1 by 88.1 mm (7.07 by 3.47 by 3.47 in.).

I²C (INTER-INTEGRATED CIRCUIT)

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I²C (Inter-Integrated Circuit), pronounced I-squared-C or I-two-C, is a multi-master, multi-slave, packet switched, single-ended, serial computer bus invented by Philips Semiconductor (now NXP Semiconductors). It is typically used for attaching lower-speed peripheral ICs to processors and microcontrollers in short-distance, intra-board communication. Alternatively, I²C is spelled I2C (pronounced I-two-C) or IIC (pronounced I-I-C).
Since October 10, 2006, no licensing fees are required to implement the I²C protocol. However, fees are still required to obtain I²C slave addresses allocated by NXP.

SMBus, defined by Intel in 1995, is a subset of I²C, defining a stricter usage. One purpose of SMBus is to promote robustness and interoperability. Accordingly, modern I²C systems incorporate some policies and rules from SMBus, sometimes supporting both I²C and SMBus, requiring only minimal reconfiguration either by commanding or output pin use.
I²C uses only two bidirectional open-drain lines, Serial Data Line (SDA) and Serial Clock Line (SCL), pulled up with resistors. Typical voltages used are +5 V or +3.3 V, although systems with other voltages are permitted.
The I²C reference design has a 7-bit or a 10-bit (depending on the device used) address space.Common I²C bus speeds are the 100 kbit/s standard mode and the 10 kbit/s low-speed mode, but arbitrarily low clock frequencies are also allowed. Recent revisions of I²C can host more nodes and run at faster speeds (400 kbit/s Fast mode, 1 Mbit/s Fast mode plus or Fm+, and 3.4 Mbit/s High-Speed mode). These speeds are more widely used on embedded systems than on PCs. There are also other features, such as 16-bit addressing.
Note the bit rates are quoted for the transactions between master and slave without clock stretching or other hardware overhead. Protocol overheads include a slave address and perhaps a register address within the slave device, as well as per-byte ACK/NACK bits. Thus the actual transfer rate of user data is lower than those peak bit rates alone would imply. For example, if each interaction with a slave inefficiently allows only 1 byte of data to be transferred, the data rate will be less than half the peak bit rate.
The maximal number of nodes is limited by the address space and also by the total bus capacitance of 400 pF, which restricts practical communication distances to a few meters. The relatively high impedance and low noise immunity require a common ground potential, which again restricts practical use to communication within the same PC board or a small system of boards.

SERIAL COMMUNICATIONS - RS-485

RS-485, also known as TIA-485(-A), EIA-485, is a standard defining the electrical characteristics of drivers and receivers for use in serial communications systems. Electrical signaling is balanced, and multipoint systems are supported. The standard is jointly published by the Telecommunications Industry Association and Electronic Industries Alliance (TIA/EIA). Digital communications networks implementing the standard can be used effectively over long distances and in electrically noisy environments. Multiple receivers may be connected to such a network in a linear, multi-drop configuration. These characteristics make such networks useful in industrial environments and similar applications.

The EIA once labeled all its standards with the prefix "RS" (Recommended Standard), but the EIA-TIA officially replaced "RS" with "EIA/TIA" to help identify the origin of its standards. The EIA has officially disbanded, and the standard is now maintained by the TIA. The RS-485 standard is superseded by TIA-485, but often engineers and applications guides continue to use the RS-485 designation.
RS-485 supports inexpensive local networks and multidrop communications links, using the same differential balanced line over twisted pair as RS-422. It is generally accepted that RS-485 can be used with data rates up to 10 Mbit/s and distances up to 1,200 m (4,000 ft), but not at the same time. A rule of thumb is that the speed in bit/s multiplied by the length in meters should not exceed 108. Thus a 50-meter cable should not signal faster than 2 Mbit/s. Under some conditions, it can be used up to data transmission speeds of 64 Mbit/s.

In contrast to RS-422, which has a single driver circuit which cannot be switched off, RS-485 drivers use three-state logic allowing individual transmitters to be deactivated. This allows RS-485 to implement linear bus topologies using only two wires. The equipment located along a set of RS-485 wires are interchangeably called nodes, stations or devices. The recommended arrangement of the wires is a connected series of point-to-point (multi-dropped) nodes, i.e. a line or bus, not a star, ring, or multiple connected networks. Star and ring topologies are not recommended because of signal reflections or excessively low or high termination impedance. If a star configuration is unavoidable, special RS-485 star/hub repeaters are available which bidirectionally listen for data on each span and then retransmit the data onto all other spans.

Ideally, the two ends of the cable will have a termination resistor connected across the two wires. Without termination resistors, reflections of fast driver edges can cause data corruption. Termination resistors also reduce electrical noise sensitivity due to the lower impedance. The value of each termination resistor should be equal to the cable characteristic impedance (typically, 120 ohms for twisted pairs). Somewhere along the set of wires, pull up or pull down resistors are established to fail-safe bias each data wire when the lines are not being driven by any device. This way, the lines will be biased to known voltages and nodes will not interpret the noise from undriven lines as actual data; without biasing resistors, the data lines float in such a way that electrical noise sensitivity is greatest when all device stations are silent or unpowered

3 Steps to Understand RS232 Devices

 

Having troubles with controlling your RS232 device? This article will certainly help you understand almost all of the hardware and software standards for RS232.

Step 1: Understand RS232 Connection & Signals

RS-232C, EIA RS-232, or simply RS-232, refers to the same standard defined by the Electronic Industries Association in 1969 for serial communication.
DTE stands for Data Terminal Equipment. Any computer is a DTE. DCE stands for Data Communication Equipment. Any modem is a DCE.
DTE normally comes with a Male Connector, while DCE comes with a Female Connector. However, that is not always the case. Fortunately, there is a simple way to confirm this:
Measure Pin 3 and Pin 5 of a DB-9 Connector with a Volt Meter, if you get a voltage of -3V to -15V, then it is a DTE device. If the voltage is on Pin 2, then it is a DCE device. Simple and easy.
A straight-through cable is used to connect a DTE (e.g. computer) to a DCE (e.g. modem), all signals in one side connected to the corresponding signals in the other side in a one-to-one basis. A crossover (null modem) cable is used to connect two DTE directly, it does not require a modem in between. They cross-transmit and receive data signals between the two sides and there are many variations on how the other control signals are wired.

Step 2: Learn about the Protocol

A protocol is one or a few sets of hardware and software rules agreed to by all communication parties for exchanging data correctly and efficiently.
Synchronous and Asynchronous Communications
Synchronous Communication requires the sender and receiver to share the same clock. The sender provides a timing signal to the receiver so that the receiver knows when to "read" the data. Synchronous Communication generally has higher data rates and greater error-checking capability. A printer is a form of Synchronous Communication.
Asynchronous Communication has no timing signal or clock. Instead, it inserts Start / Stop bits into each byte of data to "synchronize" the communication. As it uses fewer wires for communication (no clock signals), Asynchronous Communication is simpler and more cost-effective. RS-232 / RS-485 / RS-422 / TTL are the forms of Asynchronous Communications.

Drilling Down: Bits and Bytes

Internal computer communications consist of digital electronics, represented by only two conditions: ON or OFF. We represent these with two numbers: 0 and 1, which in the binary system is termed a Bit.
A Byte consists of 8 bits, which represents decimal number 0 to 255, or Hexadecimal number 0 to FF. As described above, a byte is the basic unit of Asynchronous communications.

Step 3: Control your RS232 devices

After reading and understanding the first two steps we’ve talked about, it is easy to now test and controls your RS232 devices in order to get the perfect feel of how they work.
ReadyDAQ offers software solutions for RS232 devices, make sure to check them out.

Simple Wiring of Clock and Trigger

One last part of "non-standard" information obtaining and control frameworks is the manner by which bigger frameworks are synchronized. Regularly, it is important that you know "what" happened, as well as "when" it happened. In little frameworks, this is normally simple to fulfill as the simple sources of info and even the yield excitation, are on a similar board. Be that as it may, frameworks with high channel include and, specific, applications spread over extensive zones require cautious thoughtfulness regarding timing. A top to bottom talk of this theme is well past the extent of this article, yet the accompanying brief segment may help the per user begin off in the correct bearing instantly.

Simple Wiring of Clock/Trigger

Simple Wiring of clock and trigger signs is regularly the snappiest, least demanding and most exact approach to synchronize occasions in better places. Most DAQ gadgets have at least one trigger/clock sources of info and it is as often as possible conceivable to just synchronize frameworks by interfacing these signs. Take note of that the engendering of an electronic flag in a wire is near the speed of light. A thousand feet of wire would commonly just present about a microsecond of postponement.
A great many people consider GPS (Global Positioning System) as a reasonable approach to discover the closest corner store or pizza parlor. Be that as it may, GPS is likewise a magnificent innovation for giving extremely exact time data. Truth be told, the whole reason for the GPS framework is amazingly exact timekeepers (and in addition satellites at known areas). Indeed, even a generally economical GPS can give supreme planning precision superior to 1 microsecond. In spite of the fact that the GPS on your pontoon or auto might not have a period yield flag, numerous reasonable GPS gadgets give a 1 or 5 Pulse for every Second flag exact to inside 1 uS of supreme UTC. Utilizing these straightforward and reasonable gadgets, it turns out to be straightforward to synchronize information tests anyplace on the planet.

Do You Know About RS-232/422/423/485?

Individuals initially started anticipating the downfall of RS-232 in the 1980s. Obviously, RS-232 is still around and kicking. On the off chance that Mark Twain was as yet alive, I'm certain he'd compose something on the request of "The reports of the demise of RS-232 have been enormously overstated". The RS-arrangement ports remain to a great degree basic in the information procurement and control field.
RS-232 is more established and slower than its 422/423/485 family mates, yet the use of both is still extremely normal. As a genuinely straightforward interface, there is not all that much to consider while determining an RS-arrangement interface, yet a couple words might be all together. In the first place, not every single serial gadget work at a similar speed. Make certain to determine a gadget that will deal with the baud rate of your gadget. Second, for steady and reliable operation, particularly at higher rates, make certain to choose a gadget with a significant FIFO. Take note of that RS-232 ports, and specifically, those on more established gadgets, utilize equipment handshaking signs, for example, "Prepared to Send", "Clear to Send".
Numerous more up to date RS-232 interfaces don't bolster these handshaking signals, so make sure to watch that your serial interface underpins what you require. Another normal arrangement of inquiries emerges while considering the contrasts between RS-422, 423 and 485. RS-422 utilizations a two-wire, completely differential flag interface. RS-423 utilizations the same signal levels, however, utilizes just a single of the two wires. RS-422 and RS-485 are practically indistinguishable. The distinction is that an RS-485 is networkable and can be associated with various serial gadgets. An RS-485 interface will quite often be superbly appropriate for conversing with an RS-422 gadget

Data Acquisition Modules

GSM/GPRS Module 

For long range, remote duplex information correspondence, General Packet Radio Service (GPRS) correspondence is reasonable possibility to execute the assignment. The information bundle will send over GPRS and transferred into information stockpiling cloud. A quad-band 850/900/1800/1900 MHz GSM module is played out the information transmitter. The GSM module implanted with TCP stack which permits information transfer into a web server. With existing telco arrange benefit on wide spreading the system zones and satellite correspondence, the information could be sent and got the most area on the globe.

Temperature and humidity sensor 

DHT11 is a negligible exertion temperature and dampness sensor that contains an adjusted propelled hail yield for temperature and wetness. The sensor has ±5% accuracy for 20-80% sogginess range and ±2ºC precision for temperature from 0-50ºC. 5 VDC required working this sensor.

Analog Voltage Divider 

The Analog Voltage Divider V2 ready to perceive voltage from 0.0245V to 25V. The module talks with the microcontroller by methods for ADC channel, which serves 10-bit ADC. The sensor relies on upon the possibility of voltage divider, which the think voltage is scale diminished by five times, changed over into electronic examining, extend more than 1024 (10-bit) and times with most extraordinary 25V as perform in condition
To begin with, the GSM/GPRS module will attempt to develop the relationship with GPRS arrange. Once GPRS affiliation is set up, the GSM/GPRS module will affirm the developed relationship by tolerating the framework information of the banner quality and framework selection through the UI window. By then, consistent clock (RTC) module is gotten to through I2C interface to get the present time. The SD card is gotten to by methods for SPI interface and another CSV spreadsheet archive is made. In the event that the record presently exists, the data inside the report will be overwritten.
Each of the five sensors started taking estimation on the parameter; temperature and stickiness watched equipment voltage and current and the wonder contraption voltage and current. The recorded estimations are saved in the CSV report close by date and time stamp. The recorded estimation will be sent over GPRS relationship with the remote checking database. In case the data sending crash and burn, the microcontroller will retransmit the data to the remote watching server. The remote watching database server will have gotten the procured data and demonstrate these data in like the way in perspective of the parameter consigned. The site is open gotten to, however, the data from the remote watching database can be gotten to by the affirmed customer in a manner of speaking.

The Temperature and Clamminess Sensors

The temperature and clamminess sensors are skilled in recognizing encompassing changes. One of the present sensors is used to recognize current of apparatus to be checked while the other one is used to distinguish the consistent data watching contraption. A comparative operation furthermore associated with both voltage sensors, where one of the voltage sensors is used for the ceaseless data checking device and the other one is used for central rigging watching.
Most of the sensors data scrutinizing will select the microcontroller unit nearby date and time stamp synchronously. The data will be exchanged over GSM/GPRS module to remote checking database to give the customer the steady data, meanwhile, the data is marked into microSD module. The data is open wherever through web base application where the data set away inside appropriated stockpiling application. The web base application fills in as remote data securing application which demonstrates steady numerical data and graphical data plotting. In this manner, the data is accessible wherever and any kind of web capable electronic contraptions, for instance, tablet, desktop, and PDA. The data accumulated by the sensors will be moved into site server and these data will be revived at the site-specific channel and appeared for an overview. The data will be invigorated at consistent interims.
A microcontroller carries on as a little farthest point PC on electronic gear building. The microcontroller will choose how the contraptions peripherals that annexed to it work and go about as fused system which in this way altered and expand into the microcontroller streak memory. The electronic peripherals that associated with the microcontroller talk with each other through serial correspondence either by methods for Inter-Integrated Circuit (I2C), Serial Peripheral Interface (SPI) or Universal Asynchronous Receiver/Transmitter (UART). In this wander, Atmel Atmega2560 microcontroller is played out the gear operation control and serial data taking care of an errand. The microcontroller involves 54 propelled data/yield pins where 15 of it can be used as pulse width adjust (PWM)

Real Time Data Monitoring

Continuous data checking is a fundamental reinforce application to screening maintained electrical
device conditions especially when the watched parameters affect the maintained rigging electrical
contraption operation, for instance, temperature, moisture, voltage, current and wind condition.
Web embedded advancement makes data trading and openness around the globe possible where
the machine could talk with PC in playing out its operation. The likelihood of remote data transmission is
to give device straightforwardness instead of wired system and lower cost for long range correspondence.
Now and again, the normal human site visit is not sensible as a result of a couple of factors, for
instance, security, unsavory scene, huge cost per visit, atmosphere condition and risk regular life. To
beat the issues, a whole deal long-run remote watching system, which needed low help essential to
be set up. In nowadays Internet of Things (IoT) period, the sensor data reviewing can be live
sustained into a web page and can be gotten to wherever if web get to is acceptable. In taking the
upside of nowadays advancement achievement, an unmanned checking structure can be set up to
beat the communicated inconveniences. On top of that, by setting up the ceaseless watching
structure, the human site visits for plan and upkeep could be restricted.
Consequently, wander and work costs could be in like manner restricted. In this investigation
broaden, a persistent remote data checking sensors contraption is delivered close by online data
securing (DAQ) system for simple to utilize data get to.