Battery charging and discharging device remote control system based on RS 485 bus - Power Circuit - Circuit Diagram

As a main DC power source, the battery plays an important role in various fields such as industry, aerospace and civil. In the regular battery charging and discharging operation and maintenance, the existing charging and discharging device has a long working time and low working efficiency; the state of the charged and discharged battery cannot be monitored in time, and the working environment of the charging and discharging site is bad, which is detrimental to the operator. Health. Aiming at these problems, a remote control intelligent charging and discharging device is designed. The device mainly transmits the collected battery voltage and current signals to the upper computer-PC through the lower computer-single-chip microcomputer, and then realizes the charging and discharging control and real-time status display through the visualized human-machine interface. Considering that the system has strong anti-interference ability, long transmission distance, simple engineering wiring, suitable for expansion and easy control, RS 485 bus is used to realize long-distance data transmission.

1 Overall design of remote communication

The RS 485 used in this system is a half-duplex interface, a two-way single-channel connection. In the whole system, he uses a twisted pair cable to connect the charging and discharging devices distributed in different geographical locations together. In each device, the single chip acquisition module and the command control module are used as the lower position machine. A schematic diagram of its network structure is shown in Figure 1. The serial port of the PC is connected to the network through a 232-485 converter. In addition, the half-duplex low-power transceiver device MAX485 is added to provide conversion between the TTL level and the RS 485 interface level for the microcontroller. The differential balanced transceiver MAX485 is an interface chip for RS 485 that integrates one driver and one receiver. A drive that is in a disabled state and multiple receivers are attached to the transmission line without affecting the normal transmission of the signal, so multiple drives and receivers can share a common set of transmission lines. There are 32 stations on the network, each with a fixed address. Only one site can send data at the same time, while other sites can only be in receiving state to avoid data collision errors.

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