RS232 to ethernetA converter is a device that transfers data between a serial port (also known as a communication/COM port) and an Ethernet local area network (LAN).It's a two-way communication. Two-way communication allows each device to receive and transmit data.Serial devices use different pins to receive and send data, and using the same pins limits communication to half-duplex.This means that information can only travel in one direction at a time.The use of different pins allows full duplex communication, where information can be transmitted in both directions at once.
The basic application functions of the RS232 to Ethernet converter are shown in the following figure, which realizes bidirectional data transmission between RS232/485 and Ethernet.RS232 and RS485 serial ports work independently at the same time and do not affect each other.
The modbus gateway can also realize two-way communication function. On this basis, the Modbus gateway can also be used as a host.In the host mode, the Modbus gateway will automatically query the slave according to the data required by the host and save it to the cache.There is a diagram below. Let's first understand what the Modbus gateway is? And how to apply it.
The modbus gateway is a standard industrial communication protocol transmission gateway,It is also a commonly used method to connect industrial electronic equipment.Modbus allows data transfer between many devices that are communicatively connected to the same RS485 network.For example, in the agricultural greenhouse, the temperature or humidity data collected by the sensor is transmitted to the remote control center connected to the Modbus gateway.Real-time monitoring of data and timely control of site conditions.
There are three main differences between modbus and RS232 to Ethernet converter.
(1) Used as a host
As mentioned above, Modbus can be used as a host.The slave mode of the Modbus gateway is the same as the RS232 to Ethernet converter and will not be described here.When the modbus gateway is used as a host, it queries the terminal slave based on the demand data of the connected serial host device.Generally, Modbus can realize one-to-many (one master to many slaves) and many-to-many modes.It is important to note that the Modbus gateway module does not parse any protocol during transmission.Only the serial port data is sent to the network. As shown in the figure below
(2) The storage function can be realized
Opening the Modbus storage function can accelerate the query speed of the network host, which is suitable for the multi-host query mode.For example, when multiple hosts query the data of one slave, or one host needs to query the data with high frequency, turn on
Modbus storage function can save the time of serial port query faster and reduce the timeout time.
(3) The reporting function can be realized
According to the instructions set by the modbus gateway, actively query data from the serial port and actively upload the data to the network host.
Because the modbus gateway has the function of bidirectional transparent transmission, when most of the serial ports are connected with the Ethernet,RS232 to Ethernet converter can be directly replaced by modbus gateway to meet networking requirements.Some RS232 to Ethernet converter have the function of modbus gateway, but this function only realizes the transmission of modbus protocol.It cannot be used directly as a modbus gateway.Therefore, if you have a project that requires bidirectional transmission of serial data and modbus protocol conversion,RS232 to Ethernet converter or modbus gateway can be considered; If in addition,If you also need to use the modbus gateway as a host or to use the storage function, you need to select the modbus gateway device.
