10. Modbus TCP/IP

The ETH-100 interface supports Schneider Electric’s Modbus TCP/IP protocol, release 1.0. The ETH-100 is conformance class 0 and partial class 1 compliant, and allows up to 8 simultaneous Modbus TCP/IP client connections (sockets). Socket timeouts are set to 30s, which means that if a particular open socket experiences no activity for more than 30s, then the interface assumes that the client has experienced some sort of unexpected problem, and the ETH-100 will close that socket.

10.1 Drive Channel Access

Each specific drive channel (Channel A, Channel B and Channel C) is accessed via the “Unit Identifier” (UI) field of a Modbus TCP/IP packet. Drive channel A is accessed when the UI field is set to “1”, channel B is accessed when the UI field is set to “2”, and channel C is accessed when the UI field is set to “3”. Any other UI setting is invalid and will result in a GATEWAY PATH UNAVAILABLE exception (Modbus TCP/IP exception code 0A).

10.2 Supported Modbus Functions

The ETH-100 interface supports the Modbus TCP/IP function codes indicated in Table 1.

Table 1: Supported Modbus TCP/IP Functions

Function Code

Function

Class

3

Read multiple registers

0

6

Write single register

1

16

Write multiple registers

0

27