one. Door machine lifting equipment's particularity:
The safety requirements for door crane lifting equipment are becoming more and more prominent. The concept of safety first is more and more important in the control. According to regulations, the double-track synchronous correction control must be added to the large-span door machine over 40 meters to prevent left and right double tracks. The wheels of the door machine are overrunning and the track is even derailed. Due to safety requirements, the left and right double track wheels of the door machine need more synchronous control. The reliable feedback of speed, location and other information directly relates to the safe and reliable control, and the door The environmental special features of the crane lifting equipment also determine the particularity of the selection of these signal sensors and transmissions:
1. In the complex work environment on site, inverters, large motors, and high- and low-voltage power systems often have their signal cables routed together with power lines. The electrical interference at the site is severe.
2. Equipment mobility, long moving distance, difficult grounding.
3. The distance required for signal transmission is far, and the safety and reliability of signal data are demanding.
4. Synchronous control requires high real-time and reliable signal transmission.
5. Many of them are used outdoors. They require high levels of protection and temperature levels. Workers have low levels of training and require high product tolerance.
two. The significance of absolute multi-turn encoders in door crane lifting equipment applications:
In the use of position sensors for door crane lifting equipment, there are potentiometers, proximity switches, incremental encoders, single-turn absolute encoders, multi-turn absolute encoders, etc. In comparison, potentiometer reliability is low. , The accuracy is poor, there is a dead zone at the use angle; the proximity switch, ultrasonic switch and so on are only signals at a single point and not continuous; the
Incremental Encoder signal has poor anti-interference, the signal cannot be transmitted far away, and the power failure position is lost; single-turn
Absolute Encoder Can only work in 360 degrees, if the variable speed to expand the measurement angle, the accuracy is poor, if the use of memory through a single lap to achieve multi-turn control, after a power outage, due to wind, down or artificial movement and loss of position. Only absolute value multi-turn encoders can be safely used in door crane lifting equipment. They are not affected by power outage jitter, can be long-distance, multi-turn operation characteristics, all internal digital, anti-jamming, signals can also be achieved Long-distance security transmission. Therefore, from the point of view of the safety of the crane lifting equipment, the absolute value multi-turn encoder is an inevitable choice.
three. The application of Canopen absolute encoder in the crane lifting equipment recommended CAN-bus (Controller Area Network), ie Controller Area Network, is one of the most widely used open field buses in the world. As a remote network communication control method with advanced technology, high reliability, complete functions, and reasonable cost, CAN-bus has been widely applied to various automatic control systems. For example, CAN-bus has unparalleled superiority in various fields such as automotive electronics, automatic machinery, intelligent buildings, power systems, security monitoring, marine shipping, elevator control, fire safety, and medical equipment, especially at present. High-speed railways, wind power, and Can-Bus are the preferred signal standards.
CAN-bus development and maintenance with its low cost, high bus utilization, very long transmission distance (up to 10Km), high-speed transmission rate (up to 1Mbps), priority based multi-master structure, reliable The error detection and processing mechanism fully compensates for the low bus utilization, single master-slave architecture, and lack of hardware error detection of traditional RS-485 networks, enabling users to build a stable and efficient fieldbus control system, resulting in the largest actual value. In harsh environments such as lifting equipment, because Can-bus has a reliable signal error detection and processing mechanism, it can still transmit data well for strong interference and non-reliable grounding, and its hardware error self-check, The redundancy of multi-master station ensures the safety of the control equipment.
Canopen is an open protocol based on the CAN-bus bus and managed by the CiA Association. It is mainly used in the vehicle industry, industrial machinery, intelligent buildings, medical devices, marine equipment, laboratory equipment, and research fields. The Canopen specification allows the broadcasting of messages. It also supports point-to-point transmission and reception of data. Users can perform network management and data transmission operations through the Canopen object dictionary. In particular, Canopen has the features of anti-jamming and multi-master applications, which can form an actual master station redundancy backup and achieve a more secure control.
Compared with other signal formats, Canopen is more reliable, more economical, and more secure (device error). Comparison of these characteristics with other outputs: parallel output signal - excessively fragile output power components, excessive breakage of the core wire and high cost of the cable; SSI output signal - referred to as a synchronous series signal, when the signal is far away or disturbed, the signal The delay causes the clock and data signals to no longer be synchronized, and data transitions occur; Profibus-DP bus signals - high requirements for grounding and cabling, high costs, no master station selectability, and once the bus connection gateway or master station fails Causes the entire system to be flawed. The use of the above mentioned in the lifting equipment can sometimes be fatal, so it can be said that the Canopen signal is more reliable, more economical and safer to use in lifting equipment.
Shanghai Quanpu Electromechanical's Canopen Absolute Encoder, because of its high-speed signal output, in the function setting, the absolute position of the encoder can be set to be output together with the change speed value, for example, the first two bytes of output absolute Value angle (can be multi-turn) position, third byte output speed value, fourth byte output acceleration value (optional), this is helpful in the case where the hoisting equipment has applied inverters, the speed value can be As the feedback of variable frequency speed regulation, the position value can be used as precise positioning and synchronous control, and there can be double closed loop control of speed and position, so as to achieve accurate positioning, synchronous control, parking anti-sway, safety zone control anti-collision, speed safety protection, etc. , And Canopen's unique multi-master feature, can achieve the host controller redundant backup receiver, backup controller parameters can be set behind the main controller, once the main controller system fails, the backup controller can take the last Safety protection control, so as to achieve various safety control of lifting equipment.
The large motor of door crane lifting equipment is started and used outdoors. Its encoder signal cable is long, equivalent to a long antenna. Surge over-voltage protection at the field signal end is very important. In the past, parallel signal encoders or incremental encoders were used. There are many signal core cables, and it is difficult to achieve surge overvoltage protection for each channel (surge voltage generated by large motor startup or lightning strikes), often the encoder signal has ports burned out; and SSI signals are synchronously connected in series, such as adding waves. Surge protection, signal propagation delay destroys synchronization and signal instability. The Canopen signal is a high-speed asynchronous or broadcast transmission, and does not have much influence on the insertion of a surge protector. Therefore, if a Canopen encoder and a received controller incorporate a surge overvoltage protector, it can be used more safely.
Fives. Typical application case 1. Door machine cart synchronous walking correction - detected by two Canopen absolute multi-turn encoders to check the synchronization of the left and right wheels. The signal output to the controller of the Canopen interface is synchronously compared with PFC. Meanwhile, the Canopen absolute encoder can output the speed feedback at the same time. , Through the controller to provide inverter speed control, to achieve small correction, large correction, super-biased stop and other controls.
2. Speed Security - The Canopen absolute encoder outputs both position and velocity values (direct output without external calculations), which responds faster to speed protection.
3. Security redundancy control-Using Canopen's multi-master redundancy feature, the PFC201 controller can be dual-redundantly backed up, and the second controller can be added for security backups as required by the user.
4. Security record function, PFC201 controller with 2G SD memory card, event records (black box), in order to achieve failure analysis and to prevent worker violations (safety record check), to achieve a more secure control.
5. Parking positioning anti-swaying-Using the position and speed simultaneous output characteristics of the Canopen absolute encoder, dual closed-loop control of parking positioning and retarding deceleration can be realized, which can reasonably stop the speed and position curve and reduce the swing of the suspension point when parking.
6. Typical application introduction:
The large-diameter door crane hoisting equipment synchronous rectification control at the construction site of Guangdong Zhongshan Sea-crossing Bridge, with a span of about 60 meters, the door machine height of more than 50 meters, the total length of the two encoder signals to the PFC controller cable is 180 meters. Matching:
1. Canopen absolute multi-turn encoders - Gemple's absolute multi-turn encoders, 2: GMX425RE10RCB, IP67 protection rating, shaft IP65; temperature rating -25 degrees -80 degrees.
2. Canopen Controllers - Gemple's Canopen-based controllers: The PFC201 ------ can act not only as a master controller, but also as a redundant backup controller.
3. Canopen Signal Port Surge Protector: SI-024TR1CO (Recommended)
4. Encoder signal cable: F600K0206
