ETHY-100 Series White Paper

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  and  LTE.  If  I/O expansion  is  required,  there  is  little  choice  in  the  market.  As  an  expert  in  design  and  support  of  industrial  fanless  computers,  Neousys knows  well  the  real  situation  and  thus  provides  ETHY-100  Series,  Ethernet-based  generic  I/O  expansion  modules,  to  address  this  problem.

Why decentralized?

Better host reliability

Decentralization  here  means  moving  the  add-on  modules  out  of  the  fanless  computers  while  the  functionality  keeps  available.  Reducing the components, modules or devices in the fanless computers will reduce the complexity  of  the  host, and reliability increases as a result. Regarding to the host, the simpler,  the better. However, you still need these add-on functionalities. Therefore moving the electric components out, working independently and only sending commands and data between back and forth between the host and devices, i.e. decentralizing, is  a pretty good choice.

No thermal impact to the host

Neousys  has  worked  on  wide  temperature  industrial  fanless  computers  for  8  years.  We  have  been  dedicating  ourselves  to  optimizing  the  design  of  fanless  computers,  and  thus  we  know  every  add-on  modules  will,  to some degree,  have  an  influence  on   the  thermal design.  If  the  module  itself  consumes   high  current,  it  will  be  even  worse  because  we  can  expect  the  module  will  generate  a   lot  of  heat  during  the  operation.  And  moving  the  unnecessary  heat  sources  away  from  the   is  the  best  way  to  guarantee  the  original  design.

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 couple with noise. This  interference might cause  imprecise measurement or unexpected operation. The wire between sensors and data acquisition devices is where the interfering occurs most. Installing the data acquisition card in computers will undoubtedly result in a longer wire between the card and sensors. Therefore moving the data acquisition devices close to where the sensors is will lower the impact of external noise.

Easy Deployment and Maintenance

Decentralized devices usually have its own processor and can work independently. Since these devices are not installed in computers, having some simple MMI, i.e. buttons and LEDs, helps to clarify the situation when problems occur. With the decentralized devices when the control program hasn’t been ready, it’s possible to read the status of a proximity sensor or manually turn on a valve to check if the wiring is correct or not. It also helps when the system malfunctions. Technicians can check if sensors and actuators work fine without running the control program.

Why Ethernet?

Higher Speed

Since decentralized devices are closed to sensors and not located in the computer, there will be a communication media between the decentralized devices and the computer. In the past, RS-485, and sometimes RS-232, play a big role as the media. Nowadays, Ethernet shows a trend to get higher attention. However, many of the RS-485 devices supports only 9600 or 115200 bps. 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 without going through any switch or router, it takes around 0.083ms. Ethernet is around 1000 times faster then RS-485. Even if other potential delay is considered Ethernet is still much faster.

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 a service 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

Rich I/O Combination and Decentralization

ETHY-100 series is a group of Ethernet-based generic I/O expansion modules. With ETHY-100 series, it’s possible to have various I/O expansion, such as digital inputs, digital outputs, analog inputs and analog outputs, without any add-on module installed in the host. And you can make any combination among these modules according to your need up to 16. Each ETHY-100 module equips its own processor and can work independently even if the host or the other modules malfunction.

Daisy Chain for both Data and Power

Each ETHY-100 module has two LAN ports and enables a daisy chain topology, i.e. connecting modules one after another. With the daisy chain topology, only one LAN port of host is required to connect up to 16 modules. Not only the data goes through the daisy chain but also power is. If the first ETHY-100 module is powered by a PoE host, the other ETHY-100 modules after it can be also powered by PoE without DC input. This largely simplifies the wiring. Thought only daisy chain is mentioned, L2 switches can be used to expand to other topologies, ex. star topology.

Direct Wiring and Removable Terminal Block

ETHY-100 module is itself a terminal board. Sensors and actuator can be wired directly to an ETHY-100 module without any additional terminal board. To facilitate the maintenance, ETHY-100 modules equip with removable terminal block, where wires of sensors and actuators go to. In case that the ETHY-100 has to be exchanged or removed temporarily, it’s possible to remove the whole terminal blocks without any modification on the wires wired to them. You don’t need to take the risk of incorrect wiring after the new module installed, and by the way, it also saves your time.

I/O Status Indicators and User Configurable MMI

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 programmer can see what his or her program really does. 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. With proper programming, the technician can also manually manipulate the output by the user configurable MMI, i.e. buttons and 7-segment displays.

Support DTIO and NuMCU*

On many occasions, an output has to follow an event immediately or within some predefined delay. 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 very commonly used pattern in control applications. ETHY-100 modules has an intelligent DTIO algorithm built-in to make a fast and precise response, i.e. usually a digital output, to an event, i.e. usually a digital input. You need only input the pre-defined rules, no programming is required and everything is ready. Due to DTIO is controlled by the ETHY-100 local processor, the response time can be shorter then 1ms. This is not possible in a general purpose OS. If the pattern of DTIO is not good enough for your application, you can consider NuMCU project, which Neousys provides API for you to develop your own algorithm on ETHY-100 modules.

*) NuMCU is not included in the standard product.

Conclusion

No time for this. And the appendix. Please let me know if you think it helps.

Appendix

How DI/O is needed in an application?

 

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