Supervisory Control And Data Acquisition (Scada); Programmable Logic Controller (Plc); Modbus Tcp/Ip; Raven Modbus On Udp - Airlink101 Raven EDGE/GPRS User Manual

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Modbus/BSAP Configuration

Supervisory Control and Data Acquisition (SCADA)

Supervisory Control and Data Acquisition (SCADA) describes solutions across a large variety of

industries and is used in industrial and engineering applications to monitor and control distributed

systems from a master location. SCADA encompasses multiple RTUs, a central control room with

a host computer (or network), and some sort of communication infrastructure.

SCADA allows for "supervisory" control of remote devices as well as acquiring data from the

remote locations. Programmable Logic Controllers allow for a higher degree of automated

SCADA.

A Programmable Logic Controller (PLC) is a small industrial computer which generally monitors

several connected sensor inputs and controls attached devices (motor starters, solenoids, pilot

lights/displays, speed drives, valves, etc.) according to a user-created program stored in its mem-

ory. Containing inputs and outputs similar to an RTU, PLCs are frequently used for typical relay

control, sophisticated motion control, process control, Distributed Control System and complex

networking.

Modbus TCP/IP simply takes the Modbus instruction set and wraps TCP/IP around it. Since TCP/

IP is the communications standard for the Internet and most networked computers, this provides a

simpler installation. Modbus TCP/IP uses standard Ethernet equipment.

When AirLink modems are used in place of radios, a Raven is connected to the central station

(host) and a Raven is connected to each remote unit. When the Raven is configured for Modbus

with UDP, the Raven connected to the host can store a list of IP addresses or names with matching

IDs. When the host at the central station sends serial data as a poll request, the Raven at the host

matches the RTU ID to a corresponding IP of a Raven at a remote unit. A UDP packet is assem-

bled encapsulating the RTU ID and serial data transmitted from the host. The UDP packet is then

transmitted to the specific Raven at the remote unit matching the RTU ID. The remote Raven then

disassembles the packet before transmitting the RTU ID and serial data to the remote unit. The

remote units operate in normal UDP mode and their data is sent to the host via the remote Raven

and host modem.

Raven EDGE/GPRS for Cingular - User Guide, version 2.31

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