ControlNet ¿? ... What is that?
ControlNet is a high-speed network in real time for both transmit data I / O at a critical time to transmit messages. Includes shares of upload / download of programs, configuration data and message-to-peer (peer-to-peer), in a single physical medium. The ControlNet baud rate is 5 Mbits / s for both the control and data.
ControlNet allows multiple consoles to control I / O using the same cable. This network allows an advantage over other networks, which is to allow a single master in a single network, multicast also allowing both inputs to the data-to-peer (peer-to-peer), thus reducing traffic the net increase system performance.
ControlNet network is a deterministic and cyclic. Determined by the ability to predict when data is sent and cyclical because it ensures that the time is transmitted is constant and not dependent on the connected devices.
The network access is controlled by an algorithm of time called Concurrent Time Domain Multiple Acess (CTDMA), which regulates the opportunity for a node to transmit at each interval.
FEATURES
- Speed of 5 Mbit / s.
- Allows connection to 99 nodes.
- Each segment can cover distances of up to 1 000 m.
- The means of transmission may be coaxial cable or optical fiber.
- The amount of information sent is 510 bytes.
- The type of communication is multi-master type.
More on ControlNet download this complete documentation: 
... Is it an open network, too?
Of course. Modbus was developed by Modicon, now as part of Schneider Electric. The protocol was widely used with some modifications by many companies. There are a lot of installed systems in USA and Europe and many companies apply DCS (distributed control systems) using Modbus as their communication protocol.
... And how does it work?
During communication on a Modbus network, the protocol assigns an address to each controller, recognizing the message addressed to him, determines the kind of action to take and extract any data from other information contained in a message. If a response is required, the driver should build the response message and send it using the same protocol.
On other networks, the message contained in the Modbus protocol are labeled in a structured package which is used in the network.
... And do you use the serial interface?
The ports are standard Modbus drivers and use: serial interface RS-232C signal levels, baud rate settings and checking parity. The controllers can be connected directly to the network or via modems.
... What is the communication technology used?
Controllers communicate using technology master-slave (master-slave), in which only one device (master) can initiate transactions (queries). The other devices (slaves) respond to the request of the master. The masters typically include a central processor and programming panels. The typical slaves include programmable controllers. Modbus Plus is a high-speed version of multimaster support Modbus.
The master can address individual slaves ios can start a bradcast message to all slaves. The slaves return a reply message.
FEATURES
- Speed of 1 Mbit / s.
- Allows connection to 64 nodes.
- The maximum distance is 450 m.
- The type of communication used is Multi-Master.
SUMMARY OF INDUSTRIAL NETWORKS
AS-Interface is a low-cost network binary sensors and actuators primarily used in analog and machines and sequential control.
PROFIBUS fieldbus applications with critical response times. One of their profiles, PROFIBUS PA, is specially designed for process control tasks in areas with explosive atmospheres potencialmehte.
Profibus DP bus is for use by field at a speed of 12 Mbit / s.
Profibus FMS is for use at the cellular level, providing the link PLCs, operator panels, PCs, etc..
DeviceNet is a field primarily oriented to manufacturing processes.
Foundation Fieldbus is a protocol whose main characteristic is to distribute the control functions on the network.
Industrial Ethernet is a network that can transmit large amounts of information at high speed. Used initially on the cell level but with very large projections into the solution at the field level.
Some questions to complete
- What is the maximum length of cable used on a network without using repeaters ASI?
100 meters
- Why is it important that a protocol is independent of the manufacturer?
It is important for integration problems, and often mutually exclusive protocols, creating the need for protocol converters or buy only products from a particular supplier.
- What is DeviceNet?
DeviceNet is a network of low cost intelligent control that connects a wide range of intelligent devices such as sensors, bar code readers, actuators and other devices.
- A DeviceNet network is equivalent to the AS-I?
Right, as both connected field devices.
- What is "Foundation Fieldbus"?
It is a bidirectional serial communication system fully digital at a speed of 31.25 kbps which interconnects field devices such as sensors, actuators and controllers.
- Is standard Profibus field bus open and independent of the seller?
Right.
- When to use Profibus-PA?
It is used in applications in potentially explosive atmospheres (intrinsic EExi-Protection).
