ABB PMKHRMPBA2000A Bus Redundancy Cable

ABB PMKHRMPBA2000A Bus Redundancy Cable

Overview

Product Definition and Function: ABB PMKHRMPBA2000A Bus Redundancy Cable (Bus Redundancy Cable) is mainly used in industrial automation systems, designed to ensure the reliability and redundancy of communication buses. In complex industrial environments, the stability of the communication system is crucial. This cable can provide an alternate communication path, and when the main communication line fails (such as line damage, signal interference, etc.), it can automatically switch to the alternate line to ensure the continuous transmission of data, thus maintaining the normal operation of the entire automation system.

Working Principle

Redundancy mechanism is realised:

Physical connection method: This cable is connected in the system by constructing two parallel communication paths. For example, in a fieldbus-based automation control system, it connects the main communication bus and the standby communication bus to the communication interfaces of individual devices (e.g. PLCs, sensors, actuators, etc.). These two paths are physically independent of each other to reduce the possibility of simultaneous damage.

Signal transmission and switching logic: Under normal conditions, the system transmits data via the main communication bus. When a fault occurs in the main communication bus, such as signal interruption, high BER or line short circuit, the communication management module in the system (usually switches, controllers, etc. with redundancy management function) will detect the fault signal. The communication path is then automatically switched to the alternate bus according to a predefined switching logic, ensuring that data can continue to be transmitted between devices. This switchover process is fast to minimise the impact on system operation, with a typical switchover time of between a few milliseconds and tens of milliseconds.

Co-operation with communication protocols:

Supported communication protocols: PMKHRMPBA2000A cables are usually compatible with a wide range of industrial communication protocols, such as Profibus - DP, Profinet, etc. The cables can be used in a wide range of industrial automation applications. These protocols are widely used in industrial automation to achieve efficient communication between devices. In the case of Profibus - DP, for example, the cable ensures that the exchange of data between masters and slaves as defined by the protocol is not affected in a redundant configuration. It provides reliable physical layer support for the operation of the protocol, including signal transmission, matching of electrical characteristics, etc.

Redundancy management at the protocol level: At the protocol level, there are also corresponding redundancy management mechanisms in conjunction with the physical redundancy of the cables. For example, in the Profinet protocol, the redundancy protocol will quickly reconfigure the network topology in the event of a failure of the primary communication link, using the alternate link to establish a new communication path. The cable, as the physical transmission medium, carries the redundant signals that are processed at the protocol level to ensure that the data can be transmitted in the format and according to the requirements specified in the protocol.

Performance Characteristics

High reliability and redundancy: Its core feature is to provide highly reliable communication redundancy. The risk of system downtime due to communication line failure is greatly reduced by the dual communication path design. In industrial scenarios that require high production continuity, such as chemical production and power systems, this redundancy design ensures that the system can still operate stably even in the event of a partial communication failure, effectively improving the availability of the entire automation system.

Good electrical performance: It has good electrical characteristics, including low attenuation and low crosstalk. Low attenuation means that when the signal is transmitted in the cable, the energy loss is small, which can ensure that the signal strength after long-distance transmission can still meet the requirements of the receiving equipment. Low crosstalk, on the other hand, can prevent signal interference between adjacent lines and ensure the accuracy of data transmission. For example, during high-speed data transmission, it can effectively reduce the impact of electromagnetic interference on the signal to ensure communication quality.

Strong compatibility: Compatible with a wide range of ABB equipment and other devices that comply with industrial standards. Whether it is ABB's PLCs, remote I/O modules, or other brands of industrial equipment, as long as they support the appropriate communication protocols and redundancy features, they can all be connected using this cable. This compatibility makes it a great advantage in complex industrial system integration, allowing users the flexibility to build and expand their automation systems.

Durability and environmental adaptability: It is made of high-quality materials with good durability. The cable sheath is usually wear-resistant, corrosion-resistant, and resistant to high and low temperatures, and can adapt to harsh industrial environments. For example, in environments with a wide range of temperature variations (- 20℃ - + 60℃), high humidity (10% - 90% relative humidity), and the presence of chemically corrosive substances (e.g., in a chemical workshop), it is still able to maintain good performance and ensure long-term stable communication services.

Technical Parameters

Electrical parameters:

Characteristic impedance: generally around 120Ω, characteristic impedance matching is an important factor to ensure the efficient transmission of signals in the cable, which can reduce signal reflection and improve transmission efficiency.

Attenuation coefficient: At certain frequencies (e.g. 1MHz - 100MHz), the attenuation coefficient is low, e.g. no more than 10dB per 100 metres, which makes it suitable for communication transmission over long distances.

Crosstalk isolation: High crosstalk isolation between neighbouring pairs, e.g. more than 30dB, prevents signals from interfering with each other.

Physical parameters:

Cable type: Generally shielded twisted pair (STP) or coaxial cable, the shield can effectively prevent external electromagnetic interference into the cable, to protect the signal transmission.

Outer diameter size: The outer diameter size depends on the specific model and design, usually between 5mm - 10mm, to facilitate wiring and installation in industrial sites.

Length specification: There are various length specifications available, such as 1 metre, 5 metres, 10 metres, etc., which can be selected by the user according to the actual requirements of the installation distance.