In this issue, I will explain the communication protocol of Hex Force/Torque Sensor.
The sensor needs to adopt a suitable way to transmit the force information it feels. The rule that the sender and receiver commomly observed is the communication protocol. There are many kinds of communication protocols and many classification methods, we only explain some common communication protocols from the use angle of suitable for 6 Axis Force Torque sensor. The communication protocols commonly used in industry can be divided in to two categeories: analog communication and digital communication. For the 6 Dof Load Cell needs to output data in six directions, while the analog communication can only transmit information in one direction, so the Six Axis Load cell mainly adopts the digital mommunication protocol.
The protocol of digital communication is a series of agreements stipulated by the communication two side to communicate effectively and reliably. That is to say, the receiver( computer or terminal equipment) get the digital signals(0 and 1) transmitted by the sender(F/T sensor) through the cable, it will arrange and inerpret the received signals according to certain rules for a period of time, so as to obtain the information transmitted by the sender. This method seems to have much less infomation than the ananlog communication protocol of continously changing voltage or current, but it greatly improves the anti-interference ability and universality of transmission. Next I will explain the advantage of digital communication by actual example.
For example, a common serial BUS protocol-RS485 protocol, it stipulates that two wires are used for sending and receiving communication. When the voltage difference between the two wires is positive 2~6V, it means logic 1, while when it is negative2~6V, it means logic 0. So the supervisory computer only needs a transceiver to compare the voltage between the two lines, and the communication at this time is completed by recording 0 or 1 in accordance with the rules. It is is easy to implement in the circuit, and the computer system runs binary 0 and 1, so it is very common. For this voltage is a range rather than a specific value, it greatly improve the anti -interference ability. For example, an interfering electromagnetic wave makes the voltage between two lines change from 3V to 4V, which will not change the data results. If something can interfere with the voltage change of 1V, it must be a large energy density interference. RS485 stipulates that two wires must be differential output, when one wire is positive voltage, the other one must be negetive voltage, so that the anti-interference ability can be further improved when using twisted pair cable. RS485 protocol has such a large range of applications in the field of industrial automation because of these good features. Our common industrial computer, PLC and other equipment are basically standard with RS485 protocol serial port.
Digital output communication protocols have developed a lot in recent years, and often used in our daily life, such as USB, Ethernet and so on. In order to provide a wide range of superbisory computer devices with convenient data reception, force torque transducer will support as many communication protocols as possiable. Our transducers support RS485, RS422, USB, CAN, Ethernet TCP, Ethernet UDP, Industrial Ethernet and other protocols. These protocols just said that the communication between the sensor and the host computer using what kind of hardware, such as the communication cable used is two wires, network cable or the 8-core twisted pair cable? When the two devices comply with the same hardware protocol, we also need to negotiate how to communicate in software. Such as sending how many bits, whether there is a starting identifier, an end identifier or check and so on. I will explain the relevant content of software protocol in digital communication in next period.
This is the whole content of this period. If you want a high-quality force measurement scheme, please pay attention to Kunwei Technology. See you next time.
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