Motorola 68P02958C00-B - Manual (Page 21)

2-1
IP Gateway System Overview
SCADA System
The complete control system is comprised of the SCADA control center (or centers)
communicating with MOSCAD RTUs over various communication links, such as:
• conventional radio
• trunked radio
• data radio, dial-up lines
• leased lines,
• microwave, fiber optic links
• combined networks
The communication system is used for transmitting alarms, status and telemetry, calculated
data diagnostics and error logging information from the MOSCAD RTUs to the central facility
computer and vice versa. It is also used for downloading, monitoring and debugging the
application program at the sites.
The system may be relatively simple, comprising several RTUs and a single control center, or
a more complicated hierarchical system, where several sub-control-centers communicate with
lower, parallel and higher hierarchies. The RTUs may also communicate with each other
and/or with any other hierarchy in the system.
The MOSCAD system uses the MDLC protocol, based on the seven layers of the OSI model
published by ISO, and adapted for SCADA communications. It provides network support,
multiple logical channels per physical port, allowing each RTU to simultaneously run several
communication sessions, such as data exchange, on-line monitoring, diagnostics, etc.
The MOSCAD system is supplied with a Toolbox, which is a software package that runs on an
IBM PC (or compatible). All RTU functions such as configuration, database and process
definition, downloading, monitoring, hardware and software diagnostics, etc. are defined by
means of the MOSCAD Programming Toolbox.
Figure 2-1 describes a typical MOSCAD radio system. The IP Gateway includes one Ethernet
port for connection to the SCADA computer and 3 serial ports for communicating via MDLC
protocol to the MOSCAD devices. In this particular case, one MDLC port is connected to the
MOSCAD Programming Toolbox and the second MDLC port is connected to a radio for
communicating with the RTUs.