CAN bus interface isolation communication module based on programmable logic controller

Abstract

The invention provides a CAN bus interface isolation communication module based on a programmable logic controller. The CAN bus interface isolation communication module comprises a CAN bus interface isolation communication physical layer hardware circuit and an ISP program download and button reset circuit. The CAN bus interface isolation communication hardware circuit and software units based on digital programmable logic control are constructed by adopting an ADM3053 electromagnetic coupling driver and an EPM7032STI44-5 programmable logic controller and other master control chips with enhancement of real-time performance and anti-interference performance of CAN bus interface isolation communication acting as the starting point. The module has advantages of high hardware integration, single external power supply, simple principle, great software stability and low production cost so that reliability of CAN bus interface isolation communication can be effectively enhanced.

Description

technical field [0001] The invention relates to a bus communication technology. Background technique [0002] CAN bus network communication is widely used in vehicles and various systems. Due to the safety considerations of the product itself or the requirements of anti-electromagnetic compatibility tests, in order to control and reduce the mutual interference between the signal excitation source and the tested CAN bus network communication system, it is necessary to The CAN bus test interface is designed to isolate the communication to achieve the purpose of disconnecting the electrical connection. [0003] At present, there are two main ways to isolate the differential level of the CAN bus interface: 1) using the gateway method, using a microcontroller such as a microcontroller to relay the data link to complete the signal conversion of the CAN bus interface. This microcontroller will design two sets of CAN bus software and hardware interfaces independent of each other at...

AI Technical Summary

Problems solved by technology

[0003] At present, there are two main ways to isolate the differential level of the CAN bus interface: 1) using the gateway method, using a microcontroller such as a microcontroller to relay the data link to complete the signal conversion of the CAN bus interface. This microcontroller will design two sets of CAN bus software and hardware interfaces independent of each other at the same time, the system is complex, the real-time performance is poor, and the software program will be reconfigured when communicating between different networks, and the portability is not good; The differential level value is the design basis, and the CAN bus interface isolation communication is realized by adapting a special power supply module and a photoelectric isolator. The advantage is that the cost is low, but the disadvantage is also very obvious: +5V, +4V, +2.5V are required , +1.5V, +3V and other multi-variety voltage sources and high-precision voltage divider resistors are used together, the circuit structure is complex, the device quality requirements are high, and the anti-interference performance is poor. A slight deviation in the voltage will cause CAN bus interface isolation and communication abnormalities, and It will also feed back the fault to the CAN bus network under test, which is very impractical

In addition, programmable logic control can theoretically be realized by overlapping combinations of 74 series devices. Because it does not have an ISP interface, its flexibility is poor, and full-duplex transceiver communication cannot be performed under high load rates.

Images