Cooper Bussmann BU-945U-E 802.11 DSSS user manual Modbus TCP to RTU Gateway, Serial Menu

Cooper Bussmann Wireless Ethernet & Device Server BU-945U-E 802.11 DSSS User Manual

Modbus TCP to RTU Gateway

The Modbus TCP to RTU Gateway allows an Ethernet Modbus/TCP Client (Master) to communicate with a serial Modbus RTU Slave.

The BU-945U-E makes this possible by internally performing the necessary protocol conversion. The conversion is always performed by the BU-945U-E which is directly connected to the Modbus serial device (i.e., only this module needs to have Modbus TCP to RTU Gateway enabled).

The above example demonstrates how a Modbus/TCP Client (Master) can connect to one or more Modbus RTU (i.e., serial) Slaves. In this example the BU-945U-E Access Point is configured with the “RS232 Modbus/TCP to RTU Gateway” enabled. Once enabled, the gateway converts the Modbus/TCP queries received from the Master into Modbus RTU queries and forwards these over the RS232 port to the Slave. When the serial response to the query arrives from the Slave, it is converted to a Modbus/TCP response and forwarded via the network to the Modbus/TCP Master. If no response was received serially by the BU-945U-E within the configured Response Timeout, the BU-945U-E will initiate a number of retries specified by the configured Maximum Request Retries.

The Modbus TCP to RTU Gateway may be configured to operate on either the RS 232 or RS 485 port.

Serial Menu

RS232 / RS485 Serial Port Configuration

RS232 Port	Select the desired functionality. Select either PPP, Serial Gateway or Modbus TCP to RTU
Data Rate	The serial data rate desired. Serial data rates available range from 110bps to a maximum of 115,200bps.
Data Format	The data format desired. All the standard data formats are supported.
Flow Control	Selects CTS/RTS or None
RS232 PPP Server (Only RS232)
Username	User name to enter to access RS-232 PPP Server.
Password	Password to access RS-232 PPP Server.
Local IP Address	Select the IP address of the PPP server. The remote device may be made visible on the Ethernet or
	Wireless networks by either utilizing proxy-arp or routing. The proxy-arp feature may be enabled by
	setting the Local IP address the same as the Ethernet IP Address or the Wireless IP Address. The module
	will respond on behalf of the remote device, making it seem like the device is present on the configured
	network. Alternatively, if the IP address selected is not the same as the Ethernet or Wireless IP address,
	routing is used to pass data to the Ethernet and Wireless ports.
Remote Device IP Address	Select the IP address of the remote device. Ensure this address is not the same as any other device on
	the Ethernet or Wireless networks.

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