Communication with the user system is possible by adding a circuit board with protocol selection and using a serial method fieldbus connection. All communications (commands and messages) between the actuator and the system are transmitted over the same dedicated cable. Currently, the following communication protocols are supported by SD products.
1. PROFIBUS bus type electric actuator
1) Without repeater 1200m, with repeater up to 10km
2）Up to 32 actuators per bus without repeater, 247 actuators per bus with repeater
3）Communication distance 1200m, scan time 700ms when 30 actuators are on line
4) Loop current 20 mA, 15 volts
5）ESD emergency stop function
2. MODBUS bus type electric actuator
1）Without repeater 1200m, with repeater up to 10km
2）Without repeater up to 32 actuators per bus, with repeater up to 247 actuators per bus
3）Communication distance 1200m, scan time 700ms when 30 actuators are on line
4) Loop current 20 mA, 15 volts
5）ESD emergency stop function
6) Transmission mode: RTU baud rate: 1.2K-115K
3.HART bus type electric actuator
1）Support HART protocol version 6.0 and 7.0
2）Communication frequency: 1200bits/sec
3）Support point-to-point communication or multi-point communication
Product Features
1、The mechanical drive, motor and control circuit of the product are organically integrated and designed with non-intrusive structure. The adjustment, setting, calibration and operation of various parameters of the actuator can be done without opening the end cover through the handheld infrared remote control and the digital display of the host.
2、With valve position reset function, when the system fails, the valve position can be stopped at the pre-set position.
3、CPU memory, user set calibration data, power down can be stored for 20 years.
4、Infrared remote control adopts special IC chip and specific code, anti-interference and reliable, handheld infrared remote control can be used as parameter setter or as field operator.
5、Both continuous adjustment function and switching control function are available.
6、The actuator control circuit has self-locking function, that is, if the actuator cannot be operated after 8~1 seconds after receiving the operation command when the control valve is jammed and other unexpected situations, the control circuit will automatically cut off the power supply to the motor and the actuator will enter the protection state. Together with the actuator over torque protection switch, it forms double protection.
7、The intelligent fieldbus electric actuator not only reduces the loss in the signal conversion process and improves the anti-interference due to the digital transmission method, but also transmits the signal with high quality (very stable and reliable) and can handle high precision information. Using the actuator with fieldbus reduces the workload of a large number of cables and intermediate transition devices and wiring, so it also greatly reduces human errors and system failures.
8、Because the fieldbus has two-way communication function, the actuator is in online monitoring status, and remote programming, operation and diagnosis can be realized. Online fault diagnosis and prediction can also be carried out, and status maintenance can be implemented, so it is very convenient to use and maintain.
9、Profibus-DP fieldbus actuator adopts two shielded twisted pair cables with redundant design. The two wires in each cable are redundant with each other to achieve dual-channel operation. If one of the lines fails - break, short circuit, grounding, etc., the system can start the protection system in time! Ensure the normal operation of the whole system.
10、Profibus-DP is a high-speed (physical layer using RS485 transmission, communication rate up to 12Mbit) low-cost communication system, only two twisted-pair cables are required, which reduces a large number of signal cables and the corresponding cable troughs, bridges, distribution cabinets and other hardware, reducing the cost of the project, and to facilitate on-site wiring. According to the project needs to increase the electric actuator and field control equipment, no need to add new cables, can be connected to the original cable, not only save investment, but also reduce the workload of design and installation.
1. When the electric actuator is connected to Profibus-DP bus control system, only the bus and power line need to be connected, and the rest of terminals are not wired.
2. All parameter tables have been adjusted and set according to the factory technical conditions when the intelligent bus electric actuator leaves the factory, so users do not need to adjust and set again. If you need to check whether the actuator itself is normal before connecting to the bus control system, you can check the wiring according to the above wiring diagram.
3. Other functions and diagnostic alarms of the electric actuator with bus interface are transmitted from the adapter and I/O module to the upper computer via bus.
Modbus Communication protocols
Modbus is a serial communication protocol that was published by Modicon (now Schneider Electric) in 1979 for communication using programmable logic controllers (PLCs). Modbus has become the industry standard (De facto) for communication protocols in industry and is now a common method of connection between industrial electronics.
Modbus allows multiple (approximately 240) devices to be connected on the same network to communicate, for example, a device that measures temperature and humidity and sends the results to a computer. In a data acquisition and monitoring control system (SCADA), Modbus is often used to connect a monitoring computer to a remote terminal control system (RTU).
HART Communication protocols
HART communication protocol adopts Frequency Shift Keying (FSK) principle, which is based on Bell 202 communication standard, and the digital signal is represented by two frequencies: 1200Hz represents logic "1" and 2200Hz represents logic "0". Since the average component of the frequency signal is zero during communication, it will not affect the transmission of the analog signal, so the sine wave of these two frequencies can be superimposed on the DC4-20mA analog signal and transmitted at the same time. In this way, not only can the DC4-20mA analog signal be used, but also the same cable can be used to realize bidirectional multi-information transmission with digital signals, thus having functions such as modifying the range, damping time, PID parameters, etc., which can improve the operation quality and management efficiency of the system.
Profibus
PROFIBUS, an international, open, manufacturer-independent fieldbus standard, offers a choice of transmission speeds from 9.6 kbaud to 12 Mbaud and all devices connected to the bus should be set to the same speed when the bus system is started. PROFIBUS is a fieldbus technology for plant-level monitoring and control of factory automation and field device level data communication and control. It can realize decentralized digital control and field communication network from field equipment level to shop floor level monitoring, thus providing a feasible solution to realize comprehensive factory automation and field equipment intelligence.
Foundation Fieldbus
Foundation Fieldbus is based on the ISO/OSI open system interconnection model, taking its physical layer, data link layer, and application layer as the corresponding layers of the FF communication model, and adding a user layer to the application layer. The user layer defines unified rules for information access, mainly for the needs of automation measurement and control applications, and uses a device description language to specify a common set of functional blocks.
Hot Tags: dkj explosion-proof bus type profibus modbus hart electric actuator, China, manufacturers, suppliers, factory, buy, price, quotation
