Key Features And Protocols; Pc/Plc Considerations; Modbus Tcp/Ip - Emerson Unidrive M700 User Manual

7

Key features and Protocols

This section details the key features and protocols supported by the onboard Ethernet
interface and the SI-Ethernet option module.
7.1

PC/PLC considerations

If the subnet of the host PC/PLC is different to the subnet of the Ethernet interface, then
both the Ethernet interface and the PC/PLC, must be configured with the address of a
gateway that allows communication between the two devices.
7.2

Modbus TCP/IP

Modbus TCP/IP is one of the most widely supported industrial Ethernet based protocols
offering the functionality and simplicity of the Modbus protocol, with the flexibility of
Ethernet. Table 7.1 shows the supported Modbus function codes.
Modbus TCP/IP uses the standard Protocol Data Unit (PDU) but without the CRC bytes
and encapsulates it within a Modbus TCP/IP Application Data Unit (ADU) for
transmission. This means that the Modbus PDU is the same for both standard (RTU)
and Ethernet based transmission.
Table 7.1 Supported Modbus function codes
Code
3
6
16
23
7.2.1 Modbus TCP/IP port
The port number used for Modbus TCP/IP may be reconfigured to a different port
number using Pr S.15.005 as detailed below.
S.15.005
Minimum
Default
Type
Display Format None
Coding
A timer is available to allow a loss of Modbus communication to be managed (see
Modbus Timeout (S.15.009) for more information).
SI-Ethernet User Guide
Issue: 1
Description
Read multiple 16 bit registers.
Write single 16 bit register.
Write multiple 16 bit registers.
Read and write multiple 16 bit registers.
Modbus Listening Port
0
502
16 Bit User Save
RW, BU
Maximum 65535
Units
MODBUS_THREAD_TICK
Update Rate
_TIME
Decimal Places 0
119