Industrial fanless computers are nowadays very commonly seen in industrial applications due to its robustness and the compact-sized design. But these industrial fanless computers are usually not quite good when it comes to expansion. Though some of them provides Mini PCIe or M.2 socket, they are usually designed for communication modules, such as WiFi, LTE and sometimes fieldbus modules. If I/O expansion is required, there is little choice in the market. Neousys announces ETHY-100 series, Ethernet-based  decentralized I/O expansion modules, to address this issue.

Why decentralized?

Free the limit of expansion

As described, many industrial fanless computers feature its small size. Some of them are even smaller then a standard PCI/ PCI Express Cards. Though there are many choices of I/O cards, they are not proper for industrial fanless computers, for many compact size industrial fanless computers have mPCIe slots instead of PCI/ PCI Express slots. Even if some larger ones might accept one or two PCI/ PCI Express slots, sometimes other types of add-on cards, such as frame grabber, motion control cards, fieldbus cards and specific communication cards, have higher priorities than I/O cards. Decentralized solutions mean to move I/O cards out of the host computer, and thus get a good balance between compact host computers and possibility of expansion.

Better host reliability

Though it’s important to keep the host computer simple and clear, it’s necessary to have these additional functionalities to complete the whole system. Therefore it’s a good practice to put only necessary parts or add-on’s in the host computer and move out, or to decentralize, some functionalities as standalone devices, which works independently and only sends commands and data to the host computers. Because decentralization moves the add-on modules out of the host computers, it reduces the amount of components, modules or devices in the host computers, reduces the complexity and thus increases the reliability.

No thermal impact to the host

Considering fanless computers every add-on modules will, to some degree, have influences on the thermal design. If modules consume high current, it will be even worse because we can expect they will generate a lot of heat during the operation. And moving the heat sources away is the best way to guarantee the original design. Actually Neousys patented cassette has provided a very good solution to use add-on cards with fanless computers. Using decentralized solution, such as ETHY-100 series, is a even better choice in terms of preventing thermal impact to the host computers.

Better Noise Immunity

In the field, there is usually some electronics noise out of motors, switchgears, high voltage wire, fluorescent lamps and so on. While you are acquiring data from sensors, the raw data may be coupled with noise. This interference might cause  imprecise measurement or unexpected operation. It is the wire between sensors and data acquisition devices that interfering occurs most. Installing data acquisition cards in host computers will undoubtedly result in a longer wire between data acquisition devices and sensors. Therefore moving the data acquisition devices close to where the sensors are, which is what decentralization does, will shorten the wire between data acquisition devices and sensors and consequently lower the impact from external noise.

Better Shock or Vibration Resistance

Cables for the PCI/ PCI Express I/O cards usually come with a relatively big connector, with more weight and length, at both ends. According to Newton’s second law, the connector will suffer from large force when there is acceleration, usually resulting from shock and vibration, due to its weight. Besides, the longer the length of the connectors and more heavy the cables is, the higher bending moment they suffers. Though these connectors have screws to lock themselves, the force and bending moment still sometimes loosen the screws on connectors and lower the signal qualities. On the other hand, decentralized I/O expansion modules usually use light-weight cables with only a few twisted-pairs and small connectors, such as RJ-45, between the host and the modules. Under the some conditions, shock and vibration have less impacts on the light-weight connectors and cables.

Easy Deployment and Maintenance

Decentralized devices usually have its own processor and can work independently. When the control program on the host computer is not ready yet during development or deployment, decentralized devices make it possible to read the status of a proximity sensor or manually turn on a valve to check if the wiring is correct or not without the host computer. It also helps when the system malfunctions. Technicians can check if sensors and actuators work fine by the interfaces on the decentralized devices without standing close to operation interface which is sometime at the other side of the machine or far away. If replacement is needed, the decentralized devices can be removed directly without disassembling the host computer.

Why Ethernet?

Higher Speed

Since decentralized devices are closed to sensors and not installed inside the computer, there will be a communication media between the decentralized devices and the host computer. In the past, RS-485, and sometimes RS-232, dominated. Nowadays, Ethernet gets higher attention because of its higher speed. Many of the RS-485 devices supports only 9600 or 115200 bps, bit per second. RS-485 with 8-n-1 configuration and 115200 bps spent around 86ms to send data of 1000 bytes. If 100M LAN is used to send data of 1000 bytes payload over UDP/IP, it takes around 0.082ms. Ethernet is theoretically around 1000 times faster then RS-485. An experiment shows that a RS-485 device running 39600 bsp spends around 20 times of time more than a 100M Ethernet device does to turn on a digital output.

Off-the-shelf Technology

Because Ethernet prevails all over the world, it’s much easier to find resources from as low-level as a LAN chip to services high in the cloud. The decentralized devices with corresponding design and network environment can direct upload its data to public cloud services without additional gateways. 1G or 10G LAN chips can be used if necessary to get even higher transfer rate. Moreover, good quality cables and switches can be found with good price in the market.

Features of ETHY-100

Expand on-demand

It’s very common that machine makers and SI’s choose a system with more expansion slots than it’s actually required just because they’d like to optimize between types of stocks and future expansion even if the unit cost might be a little higher. With ETHY-100 series, a decentralized solution, one system fits all and it’s not necessary to compromise anymore. ETHY-100 series enable expanding your system on demand. When one module is insufficient, more are possible. The limited expansion slots of fanless computers can be reserved for more specialized purposes. It’s also possible not only to have digital input and digital output but also other various types of expansions, such as analog inputs, analog outputs and motion control modules and to mix up different types of ETHY-100 series in one network. With ETHY-100 series, it’s no more a difficult job to expand functionalities of any compact fanless computers, such as Neousys POC-120.

No more Terminal Board and the Host Cable

The common scene using an add-on I/O card is composed of three parts: the card installed in the computer, a terminal board for wiring and a heavy cable connecting the previous two. A terminal board is a fundamental part that everything, such as sensors, switches and actuators, connect to it because most of the time it’s not feasible to wire those devices to the card directly. The concept of decentralization is moving the I/O card out of the host computer and combine it with the terminal board. ETHY-100 series, being Ethernet-based decentralized I/O expansion modules, itself works as a terminal board, and thus no additional terminal board is required. Besides, the heavy host cable connecting to the host computer is replaced by an 0ff-the-shelf CAT-5e cable. Moreover, it has all the features of decentralization that are described in the previous section.

Daisy Chain for both Data and Power

ETHY-100 series is designed with two 100M LAN ports and supports a daisy chain topology, i.e. connecting modules one after another. It means only one LAN port of host is required to connect up to 16 modules. It’s also feasible to use a simple L2 switches to more flexible topology, such as a tree topology, though usually daisy chain meets most requirement. Not only the data goes through the daisy chain but also the power is. Part of ETHY-100 series supports PoE PD. If these modules are powered by a PoE cable, it will share the PoE power, though not standard PSE, to the ETHY-100 series next to it. It means the data and power will share the same cable and largely simplifies the wiring.

Removable Terminal Block

As described ETHY-100 is itself a terminal board, it follows that I/O devices connect directly to it without an addition terminal board. When installed in compact control panels, it’s a difficult task to insert the wire into terminal blocks, hold the wire and screw it. ETHY-100 modules equip with removable terminal blocks and make it possible to separate the wiring and installation of the module itself. This facilitates the deployment. Besides, in case of maintenance, if an ETHY-100 module has to be exchanged or removed temporarily, it’s possible to remove the whole terminal blocks without releasing the wires first. You don’t need to take the risk of incorrect wiring after the module is re-installed, and it saves your time.

Hardware ID Switch

Since it’s possible to connect up to 16 ETHY-100 series in one single host computer, echo one needs a different ID to identify itself so that the program running on the host computer knows how to interact with each module or each channel. Besides, the ID is also very important for technicians to install ETHY-100 series and wire it with corresponding sensors, buttons, valves and so on. ETHY-100 series equips with hardware ID switches. The hardware ID switches make it very easy to know who they are before the module is installed and powered and thus lowers the possibility of incorrect installation and wiring.

Status Indicators, Programmable Display and Buttons

When using a dummy terminal board, which provides nothing but distributing wires, the only way to know statues of the I/O devices is to see the monitor of the host computer. However, the monitor may not be available where one stands in front of the control panel to check wiring or I/O devices. The technician has to operate the computer,  watch the result around the control panel and run back and forth again and again. Sometimes it’s only an “exercise”, but sometime it’s dangerous doing so because unexpected actuators or valves might turn on. On ETHY-100 modules, there are I/O status indicators, which shows the status of each input or output channel. This facilitates both developing of the application program and maintenance after the system is deployed. The application programmer doesn’t need to wait for the real environment been built up. By reading the I/O indicators, the programmers can see what their programs really do. On the other hand, after the program or the whole system has been deployed, the technician can read the indicators to check the sensor and the wiring between sensors to ETHY-100 modules. There are also 3-digit 7-segment display and 2 buttons on part of ETHY-100 modules. With proper programming, the 7-segment can be used to display more information, such as number of events, error codes and so on. The 2 buttons are also programmable. They can be programmed to select the content of 7-segment display as well as to manually force the value of digital outputs.

Built-in IOBOT Subsystem

It’s common cases that digital outputs act in compliance with predefined rules. For example, when the door of a wafer etching machine is opened, the nozzle of hydrochloric acid must be closed anyway. When a tank is filled to a high level, the pump has to be stopped. Or when the set temperature is reached, turn off the compressor. This is usually achieved by periodically reading status of digital inputs in the control program and then turn on the digital output once the condition is met. This sometimes consumes a lot of CPU resources and might have a considerable delay. IOBOT is a subsystem inside ETHY-100 series. It works as if there were a robot inside ETHY-100 series executing the assigned tasks in the background without using CPU resources. And due to the nature that IOBOT works locally and independently, it shows better performance and time-determinism. For assigning IOBOT tasks, there is a Windows based program, IOBOT Configurator, which allows uses to assign types of tasks and corresponding parameters and then download them to ETHY-100 series. It’s just easy and no programming is required.

Conclusion

Preaching so much about decentralized solution is not saying it’s the best, but decentralized solution is a proper solution to optimize the compactness, reliability and expansion of functionalities. However, decentralized solution is not a cure-all. When it comes to fast response, PCI/ PCIe I/O cards, or similar proprietary bus, are the best choice. If your application can stand for some hundred micro-seconds to get the status or turn on an output, congratulation, you are eligible for enjoying all the advantages provided by ETHY-100 series with any compact fanless computers. If the only one or two expansion slots has been occupied by higher priority cards, such as frame grabber, motion control cards, fieldbus cards, think about is it better to have a larger box PC with more expansion slots, or is it better to use ETHY-100 series as an alternative to I/O cards. The latter provides an overall smaller footprint. If you encountered some difficulties which are coupled with the heavy cables, noise interference and long distance of the connected devices, maybe ETHY-100 series solves the problem no matter it’s a 19″ IPC or a palm-sized fanless computer.