The product includes 1. 1 FS-MM485A adapter.
2. 1 CD (including user manual, virtual serial port software, etc.).
FS-MM485A is an industrial-grade serial-to-Ethernet server that integrates multiple functions. Users can achieve the following functions through parameter configuration:
Ordinary serial port to Ethernet server, supports TCP or UDP, and realizes transparent data transmission between serial port and network port.
MODBUS TCP/RTU standard gateway, realize bidirectional conversion between MODBUS TCP protocol and RTU protocol.
Multiple master stations share the serial port server, enabling multiple master stations to monitor a slave serial port device or multiple slave serial port devices on a serial bus in real time at the same time.
As we all know, serial ports such as RS232/RS485/RS422 use the master-slave response mode (also called query type, polling type) to communicate. Due to the exclusive access characteristics of the serial port, there can only be one master station on a bus (or Called the master), it is impossible for multiple masters to control slaves and share data at the same time. Figure 1-1 is a typical single master RS485 communication network topology.
The multi-master shared serial port server FS-MM485A adopts time division technology, which defines the session time of one access to the serial port as a time slot. After the time slot session is completed, the serial port will be released for other master stations. Make sure all masters have fair access to data. Up to 96 master stations can access one serial port device or multiple serial port devices on a bus at the same time, support multi-master station to collect data and control in real time at the same time, and do not need to change the original software and system configuration, each master station The operation is exactly the same as when using a single master.
RS485 communication network topology There are some simple products called "serial port sharer" in the market, which can only realize the time-sharing of serial port devices among multiple master stations, that is, when one master station accesses the serial port device, other master stations can only wait and wait After the previous master station has completed the communication, the next master station can communicate with the serial device, which is usually only used for time-sharing devices such as serial printers. It cannot be used in industrial control systems for multi-master simultaneous real-time data acquisition and control of slave serial devices.