Banner SureCross DX80 Wireless Networks - Manual (Page 11)

P/N 136689
11
Banner Engineering Corp. • Minneapolis, MN U.S.A.
www.bannerengineering.com • Tel: 763.544.3164
DX80
Reference Guide
Network Basics
Physical
Data Link
Network
Transport
Session
Presentation
Application
Media Layers
Host Layers
Analog, Discrete
Data
900 MHz Radio
Unique Application
OSI Seven Layer Model - Wireless Radio Network
OSI and Wireless Networks
Though the SureCross wireless product is a proprietary wireless network and the various
protocol layers are proprietary, the wireless network can be compared to the standard
seven layer model .
Instead of wires creating a connection, the 900 MHz or 2.4 GHz radio signal transmits
the binary data, creating a radio signal “link.” There are many other technologies and
layers, but the most important result is at the application layer where the data exchanged
between network nodes is used to monitor and control events .
Physical
Data Link
Network
Transport
Session
Presentation
Application
Media Layers
Host Layers
Modbus RTU
RS-485
PLC Prog, DX80
OSI Seven Layer Model - Proprietary Modbus
RTU Network
Physical
Data Link
Network
Transport
Session
Presentation
Application
Media Layers
Host Layers
Modbus RTU
RS-485
Control Program
Ethernet
Modbus/TCP
OSI Seven Layer Model - Modbus/TCP
OSI and Modbus RTU, Modbus/TCP
Applying this analogy to Modbus RTU, the lowest layer is defined by RS-485. Modbus
RTU functions at the data link layer . The application layer is the PLC program on a PLC or
the analogous control program on any host device .
Continuing with the OSI example, Modbus/TCP packages Modbus data packets inside the
standard Internet TCP/IP protocols . EtherNet/IP functions the same way . Data moves from
the data link layer up to the top of the stack and provides consistently structured data to
use with a control program .