Airlink X EV-DO - Manual (Page 36)

Raven X EV-DO for Verizon - User Guide, version 2.34 30
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.
Programmable Logic Controller (PLC)
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
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.
Raven Modbus on UDP
When AirLink modems are used in place of radios, a Raven X is connected to the central station
(host) and a Raven X is connected to each remote unit. When the Raven X is configured for Mod-
bus with UDP, the Raven X 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 X
at the host matches the RTU ID to a corresponding IP of a Raven X at a remote unit. A UDP
packet is assembled encapsulating the RTU ID and serial data transmitted from the host. The UDP
packet is then transmitted to the specific Raven X at the remote unit matching the RTU ID. The
remote Raven X 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 X and host modem.