Ethernet I/O Controller - APPLICATIONS

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Typical applications

RS-232 connection and 8 + 8 digital I/O signals via Ethernet network

If you need to connect digital signalling (possibly together with RS-232), then I/O Controller is what you need. You can see a block diagram of such a connection (Box-2-Box mode) in the picture below.

Both I/O Controllers are in the TCP Client/Server mode, connection is initialised by the one which needs to transfer new data on it's inputs. If you use the "Keep Connection" function, the connection is held up by sending the NVT NOP (No Operation) packet every 10 seconds. If this packet is not received for longer than 50 seconds, the connection is closed and will be opened again once the network connection is ready.

In case of a power failure, you need to define a default state of the output register, which will be set when the power is restored. This state remains unchanged, until the I/O Controller connects to the other side and synchronizes it's outputs with the other side's inputs.

 

RS-232 and I/O pin control via Ethernet network

This case is similar to the one above, but the I/O Controller sends data to a computer instead of another I/O Controller. You can connect more computers to one I/O Controller, but only one can communicate at a same time. For security reasons it might be useful to define an IP address range which will be accepted by the I/O controller.

Typically you can communicate with a program running on your computer (for testing purposes you can use the "Test mode" in Hercules software) which directly supports NVT communication with digital inputs/outputs.

Hercules is a TCP Client software, if you wish it to report input changes, you can switch it to TCP Client/Server as in the previous example. The computer mentioned here doesn't have to be your PC, it could also be your network server running an application.

I/O pin control from your WWW pages or user interface

A typical application can be controlling a remote machine through a WWW interface. Due to the difficulty of implementing WWW interface into the I/O Controller, it can be preferable to realise this by PHP or ASP script running on your server, which can open the connection to the I/O Controller, read inputs, set outputs and then show the results on a WWW page. You can see the communication scheme in the picture below.

This way may seem to be more complicated, but it has only one disadvantage - you need a running web server, which is very common in today's industrial systems. The advantages of this solution are:

• Programmers can create the user interface in PHP or ASP language, there is no need to learn something new, therefore your system can be launched in much shorter time.
• The robust server is much more resistant against hacking or distributed attacks.
• The acquired data can be processed and stored for example to an SQL database.
• In case of a server failure, the administrator can still connect to the I/O Controller manually.
• WWW pages can be easily modified with user access restrictions (some users can modify the data, some can only see them).
• More servers can access the I/O Controller. The number of users is unlimited, you can apply IP address restrictions.

I/O Controller applications samples

There is a huge amount of possible I/O Controller applications. For your information, we have chosen some of the applications realised by our customers.

• Manufacturing and employee management from the ORACLE server
  I/O Controller is connected to an LCD display via the RS-232 line and the inputs/outputs are connected to 8 backlit buttons. The employee presses the button with the desired activity (for. example: he wants to stop production to service a machine). The request is sent as a TCP/IP packet to the ORACLE server, which allows the activity by backlighting the pressed button, or denies the request and then sends the reason of denial to the LCD display.
  
• Simple access system
  I/O Controller is connected to the contactless id-reader (RS-232). Whenever an id is read, the packet is sent to the server, which then opens the door for the employee. By setting up the other digital outputs, the server can also activate the alarm, or turn off the lights in the guarded object when the last employee leaves and locks the door.
  
• Remote RESET of a locked-up network device
  I/O Controller controls a reset switch, or a relay, which can turn the device off. Operator can reset several devices using a simple PHP script.
  You can connect a UPS control relay, so the system can inform you that a device had a power failure and is running from battery only. Then you can use a much cheaper UPS without SNMP monitoring.
  
• Remote temperature measurement with the posiibility to turn on heating/cooling
  The I/O Controller is connected to a simple RS-232 thermometer, and the digital inputs are connected to a bimetal heat regulator. digital outputs control the heating/cooling. The server periodically reads the temperatures from the RS-232 thermometer, if the temperature exceeds the given limit, I/O Controller initiates a connection. The operator can use the digital outputs to perform important service, which cannot be done automatically.
  
• Alarm report from an emergency alarm device
  Emergency alarm is conntected to one of the I/O Controller's inputs, which reports anything unusual to the server by sending a packet. This is much faster then alert via the phone line.
  This is much safer, because the server can always check the alarm state, therefore you have much higher safety level and lower phone charges. Of course you can always run both systems in parallel.
  
• Simple parking-stand system
  One I/O Controllers input is connected to a sensor, which detects presence of a car in the parking stand. The output can be connected to a lever, which blocks access to this stand for a certain customer.
  The Ethernet connection is very cheap, robust and the system can easily be implemented into any server. The number of connected parking stands is practically unlimited. You can use the RS-232 line to connect a display which can guide the customer to the nearest free parking place.