Why use fieldbus technology to introduce instructions

Typically, both the sensor and the actuator are connected to the controller via a 4-20 mA analog signal, and a 2-core cable is required between each sensor or actuator and controller. In addition, each sensor and actuator must have an input/output loop. If a fieldbus system is used, the situation is completely different: all devices will be connected to the bus cable and the input/output circuits will be replaced by the interface board. This reduces the size of the control cabinet and greatly reduces wiring costs. In a typical control system, the transmission of signals is unidirectional (ie, only from the sensor to the controller or from the controller to the actuator). However, in a fieldbus system, the transmission of signals can be bidirectional. In addition to the actual process parameters (such as measured values and control parameters), the bus system can also transmit other parameters (such as: measuring range, filter characteristic parameters, maintenance parameters or fault signals, etc.). Therefore, the superiority of the bus system is obvious: commissioning and maintenance is simpler, system flexibility is increased, and total cost is also reduced.
■ Bus communication between the electric control unit on the island with fieldbus valve and the central control device; the bus will be a pilot valve with various fieldbus systems (PROFIBUS DP, InterBus, DeviceNet, CANopen, SELECAN, AS-Interface, Ethernet, etc.) The sensors of the interface are connected.
■ Central control equipment combined with electrical/electronic modules, valve island with fieldbus interface combined with electric pilot valve to form a new AirLINE automation system; control circuit and pilot valve installed on common rail; electronic module, power supply And the electromagnetic pilot valve and the like are plug-in type; the system is very convenient to reduce and expand; the bus communication with the internal (actuator, sensor, etc.) and the external (lower-level control device) can pass PROFIBUS DP, InterBus, DeviceNet, CANopen, Ethernet or other bus system to achieve.
For details, please refer to the manual "Fieldbus Technology" published by our company. The main contents of this manual include:
■ Fieldbus technology requirements, benefits and costs
■ Dedicated communication systems such as Profibus, Interbus, AS-Interface, Foundation Fieldbus, etc., and HART protocol
■ Fieldbus technology in hazardous areas
■ Topological considerations
■ Bus communication in the process control system
■ Comparison of various bus systems
■ Related products of our company