Modbus Bridge

A Modbus bridge is a device that connects Modbus serial products to Modbus TCP Masters. It can be an important part of a Modbus network.

Modbus Bridge Allows Communication Between Modbus Serial and TCP Devices
Modbus serial is the original variant of Modbus that travels over a serial connection. This serial connection commonly uses a RS-232 or RS-485 serial interface. Modbus TCP is an additional variant of the Modbus protocol. Internet users can access Modbus TCP at port 502, which is reserved for Modbus users on the TCP/IP stack.

Today, Modbus TCP has become an increasingly popular variant of the Modbus protocol. A Modbus bridge will allow users to transition to this variant, while still making use of their Modbus serial equipment.

A Modbus bridge may be configured as a Slave or a Master bridge, simply by connecting to either device serially. A Modbus bridge can also be used for other Modbus variants, such as Modbus ASCII and Modbus RTU.

Connect Thousands of Slaves With Just a Single Modbus Bridge
With a Modbus bridge, users can connect thousands of slave devices using a single Ethernet card and the Modbus TCP protocol. Devices connected to a Modbus bridge have individual IP addresses, and addressing slaves through the Modbus bridge is now defined by the IP address and the slave address or unit id.

When a Modbus bridge receives a Modbus TCP request, it converts the messages into Modbus RTU or another variant of the Modbus protocol, creating a response using Modbus TCP. In these cases, the Modbus master generally does not even recognize that it is not actually communicating with a Modbus TCP device.

Modbus Bridge Can Connect to Many Modbus TCP Masters at Once
A Modbus bridge can connect to many Modbus TCP masters concurrently. Serial slaves will actually recognize the Modbus bridge as the master device. The actual TCP Modbus masters will treat the Modbus bridge like a group of slaves, communicating as if each individual master had sole access to the slave devices. With more masters accessing the Modbus bridge, response times can become slightly sluggish.

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Related Products:
T/Mon NOC

To see additional information related to a "Modbus Bridge", please visit the Modbus Network page.

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