Toshiba ICC Multiprotocol Ethernet Interface ASD-G9ETH User Manual download pdf (Page 59)

ICC

13. Protocol-Specific Information

This section will discuss topics that are specific to each of the supported

protocols.

13.1 Modbus/TCP

13.1.1 Overview

The interface card supports Schneider Electric’s Modbus TCP protocol, release

1.0. The interface is conformance class 0 and partial class 1 and class 2

compliant, and allows up to 8 simultaneous Modbus TCP client connections

(sockets). Other notes of interest are:

• Supported Modbus slave functions are indicated in Table 2.

Table 2: Supported Modbus TCP Functions

Function

Code

Function Modbus TCP Class

1 Read coils 1

2 Read input status 1

3 Read multiple registers 0

4 Read input registers 1

5 Write coil 1

6 Write single register 1

15 Force multiple coils 2

16 Write multiple registers 0

• Drive registers can be addressed as either holding registers (4X

references) or input registers (3X references). For example, accessing the

output frequency involves accessing holding register 41301 or input

• Specific bits within drive registers can be accessed as either coils (0X

references) or discrete inputs (1X references).

• Because the transaction is handled locally within the interface card, write

data checking is not available. For example, if a write is performed to a

parameter object, no Modbus exception will be immediately returned.

• The “unit identifier” (UI) field of the request packets is ignored.

• The socket timeout time is determined by the “timeout” setting on the web

server’s “Config” tab (refer to section 10.7.4). This means that if a

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Toshiba ICC Multiprotocol Ethernet Interface ASD-G9ETH User Manual Page 59