ET-GT-485-1 Usage Tips

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Industrial Ethernet
Ethernet to RS485 Gateway

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This gateway is typically used in one of these situations:

¢	To pass a single user protocol (many are supported) from Ethernet to one (if TCP) or more (if UDP) slave RS485 serial devices (see "General Message Passthru" below) NEW 10/2004
¢	To connect one Modbus ASCII or RTU RS485 slave device to an Ethernet network sending Modbus/TCP commands. For Modbus/TCP applications with multiple RS485 slave stations, use the ET-GT-ST-2 or any IPm based product such as the ST-GT-1210.
¢	To connect a party-line of up to 32 Modbus ASCII or RTU RS485 slave devices to an Ethernet network sending Modbus/UDP commands
¢	To connect a party-line of up to 32 SIXNET slave devices to an Ethernet network sending SIXNET Universal commands
¢	To star off of your Ethernet network to access remote SIXNET or Modbus devices at locations up to miles away

General Message Passthru From Ethernet to Serial Slaves

In October 2004, a new capability was added to this Ethernet to RS485 gateway to pass one user-selected protocol from Ethernet to one slave device (if TCP-based protocol) or multiple slave devices (if UDP-based protocol) connected to the RS485 port, and pass the response to these messages back to the master. This capability has the following specifications and limitations:

Messages must originate from the Ethernet port and be sent to the serial port.
The entire message must not exceed 255 characters and must be included in a single Ethernet packet.
The message content will not be altered in any manner. The entire contents within the IP packet will be delivered as is.
The user may specify one and only one IP port to be monitored.
Any reply from the slave device that arrives immediately after the completion of the transmission out of the serial port will be sent back to the sending Ethernet station. The reply must fit within and be contained in a single Ethernet packet. Only one reply will be accepted and passed on to the Ethernet IP address and source port number of the originating stations.
User settable time out will be used to determine the end of the reply message. Only after the completion of the reply or the timeout waiting for a reply will a new message be processed from the Ethernet port. (The Ethernet incoming buffer will buffer messages.)
This device supports a maximum of two TCP sessions and any number of different UDP sources. The choice of TCP or UDP is automatic, both being accepted.
This device will not pass serial port initiated messages to the Ethernet port. There is no way to connect a master device to the serial port and run this device in reverse of its intended function. This device provides no means to associate an IP address with any message received on the serial port (except to reply to a message as specified above.)

Note: SIXNET does not guarantee this device and this capability compatible with any specific protocol. Suitability of this device is left to the user to determine. Refer to the 30-day trial offer in the Ordering Information for this product.