3
Introduction
SRIO 500M is a data communication and re-
porting unit for the SPACOM system. The
SPACOM system may incorporate slave devices
such as protective relays, control units and an-
nunciator units, capable of communicating via
the SPA bus.
The task of the SRIO 500M unit is to form the
master unit of the SPA bus, to connect the
SPACOM system to a host computer.
The SRIO 500M unit connects to the host com-
puter using the ANSI X3.28 or the SACO
100M protocol. The ANSI X3.28 protocol is
used with the SCS 100 or S.P.I.D.E.R Micro-
SCADA control systems. The SACO 100M
protocol can be used for the communication
with, for example, a personal computer or a
control system of a foreign manufacturer.
SRIO 500M
ANSI X3.28 or SACO 100M protocol
Display
terminal
or printer
Host computer
Feeder terminals
SPA bus
Annunciator units
