Specifications

STB NIP 2311 Services
120
EIO0000000051 6/2010
Data Exchange with the STB NIP 2311
Introduction
Data exchange between a Modbus over TCP/IP host or the HTTP embedded web
server and the Advantys STB island bus is conducted over the Ethernet port on the
STB NIP 2311 module.
Master Devices
The input and output data image areas (see page 241) can be accessed and
monitored over the Ethernet LAN by a Modbus over TCP/IP fieldbus master or the
STB NIP 2311 HTTP embedded web server.
The Ethernet port on the STB NIP 2311 is configured as follows:
z Port 502 SAP: Modbus over TCP/IP
z Port 80 SAP: HTTP
z Port 161 SAP: SNMP
NOTE: An HMI panel or a device running the Advantys Configuration Software can
also exchange data with an island through the STB NIP 2311’s CFG port
(see page 33).
Modbus over TCP/IP Communications
Master devices use Modbus messaging to read and write data to specific registers
in the process image. The Modbus protocol is understood regardless of the network
type.
The Modbus protocol uses a 16-bit word data format.
Data Exchange Process
Data stored in the process image is exchanged between the STB NIP 2311 module
and the Ethernet network through Modbus over TCP/IP. First, data from the
Ethernet host is written to the output data image area (see page 122) in the NIM’s
process image. Then, status, echo output, and input data information from the I/O
modules on the island are placed in the input data image area (see page 124). The
Modbus master can access that data through the TCP/IP network or the CFG port.
Data in the output and the input areas of the process image is organized in the order
that the I/O modules are assembled on the island bus (see page 121).