ABB TER800 Bus Terminator

ABB TER800 Bus Terminator

Overview

Product Definition and Function: The ABB TER800 Bus Terminator is an important device for industrial communication bus systems. Its main function is to provide correct signal termination matching at the end of the bus network to reduce signal reflection and ensure the quality and stability of signal transmission on the bus. In industrial bus communication environments such as Profibus, Modbus, etc., signal reflections can lead to problems such as signal distortion, increased BER, etc. The TER800 absorbs the reflected signals by means of suitable resistor matching, etc., making communication more reliable.

Working Principle

Signal reflection principle and impact: In industrial bus communication, signals are propagated in the form of electrical impulses or optical signals in the transmission medium (e.g. cable, optical fibre). When the signal reaches the end of the transmission line, it is reflected if there is no suitable terminal match. This is analogous to a water wave hitting the shore without a buffer and bouncing back. The reflected signal is superimposed on the original signal, resulting in distorted, noisy signals that can seriously affect the quality of communication. For example, in the Profibus-DP bus, the transmitted digital signals may not be recognised correctly by the receiver as a result of reflections at the 0 and 1 levels, resulting in communication errors.

Termination matching method: The TER800 uses a specific resistor network or other matching techniques to eliminate signal reflections. For buses transmitting electrical signals, this is usually done by connecting resistors at the terminals that are equal to the characteristic impedance of the transmission line. For example, if the characteristic impedance of the bus is 120Ω, the TER800 will provide a termination resistance of 120Ω. When the signal reaches the termination, this resistor absorbs the signal energy so that the signal is not reflected back, like giving the signal an ‘absorption pad’ to allow the signal to end its propagation smoothly. For fibre optic communication buses, a similar termination matching effect may be achieved by using, for example, optical attenuators to avoid reflection of the optical signal.

Co-operation with the bus system: The TER800, as part of a bus system, needs to work with other devices on the bus (e.g. PLCs, sensors, actuators, etc.). It will automatically or manually adjust the terminal matching parameters according to the type of bus (such as Profibus, CAN bus, etc.) and the requirements of the communication protocol. In some intelligent bus systems, TER800 can communicate with the host controller to receive commands about the bus status, such as determining whether to enable the terminal matching function and adjusting the size of the matching resistor during the initialisation phase of the bus.

Performance Features

Improved communication reliability: The reliability of bus communication is significantly improved by effectively reducing signal reflections. In an industrial automation environment, this means fewer communication errors and data loss, ensuring that control commands and status information can be accurately passed between devices. For example, in an automated production line, using the TER800 ensures stable communications between the PLC and motor drives, reducing line downtime due to communication failures.

Strong compatibility: It is designed to be compatible with a variety of industrial bus standards, such as Profibus - DP, Profibus - PA, CANopen and so on. This allows it to be used in a wide range of different industrial automation systems without the need to design separate terminal matching devices for each bus system. Users can choose the appropriate TER800 configuration according to the actual bus type and application scenario.

Easy to install and use: TER800 usually has simple installation methods, such as standard DIN rail mounting, for easy layout in control cabinets. In terms of use, it may only require simple parameter settings (e.g. selecting the bus type, matching resistor values, etc. in some advanced models), so that even non-expert technicians can quickly get started with installation and commissioning.

Durability and Stability: Adopting high-quality electronic components and sturdy housing design, it can work stably for a long time in harsh industrial environments. It can withstand a certain range of temperature and humidity changes, and has a certain resistance to electromagnetic interference and so on. For example, in a high-temperature, high humidity chemical production workshop environment, TER800 can still maintain good performance to ensure that the bus communication is normal.

Technical Parameters

Bus compatibility: Clearly list the supported bus types, such as Profibus - DP (up to 12Mbps), Profibus - PA (31.25kbps), CANopen (up to 1Mbps), etc., as well as the corresponding version of the communication protocol.

Termination Matching Parameters: For electrical signal buses, provide a range of resistance values for the termination resistors, e.g. 100Ω - 120Ω selectable; for fibre optic buses, state the range of optical attenuation, e.g. 0dB - 3dB etc. Other parameters such as matching capacitance, inductance, etc. may also be included (if applicable).

Physical Parameters: The external dimensions generally conform to industry standards and may range from 5cm - 10cm in length, 3cm - 5cm in width, and 2cm - 4cm in thickness, allowing for easy mounting on standard DIN rails or other mounting locations. They are lightweight, typically in the range of 50g - 200g.

Environmental parameters: Operating temperature range is generally - 20°C - + 60°C, able to adapt to the temperature environment of most industrial sites; relative humidity range of 10% - 90% (non-condensing); with a certain degree of anti-electromagnetic interference (EMI) capabilities, such as compliance with the EN 61000 - 6 - 2 (Industrial Environmental Immunity) and EN 61000 - 6 - 4 (Industrial Environmental Emission) standards.

Electrical parameters (for electrical signal buses): rated operating voltage (e.g. DC24V), maximum operating current (e.g. 100mA), etc., which determine its power supply requirements and power consumption on the bus.

Areas of application

Industrial automation production lines: In automation production lines, almost all device connections based on bus communication require good signal transmission. the TER800 can be used to connect the bus end of devices such as PLCs, robot controllers, sensors (e.g., temperature sensors, pressure sensors), and actuators (e.g., motors, solenoid valves), to ensure stable data communication in the production process. For example, in automotive manufacturing lines, ensuring reliable communication between welding robots and control systems improves productivity and product quality.

Process control system: In the chemical, pharmaceutical, food and beverage and other process control industries, it is used to connect the bus terminals of various process instruments and control devices. For example, bus connections between level meters, flow meters and control systems in chemical production ensure accurate level and flow data transmission, which is essential for precise control of chemical reaction processes.

Intelligent building automation systems: communication bus terminals for connecting devices such as lighting systems and HVAC (heating, ventilation and air conditioning) systems in a building's automation system. For example, ensuring stable communication between intelligent lighting controllers and luminaires in a building enables energy-saving control and switching of intelligent lighting scenes.