INTRODUCTION
I-E96-317A
2 - 1
SECTION 2 - DESCRIPTION AND OPERATION
INTRODUCTION
This section describes the functional operation and physical
operation of the IMRIO02 module.
describes the purpose of the RIO module. Details covered
under
are the RIO security provisions
and the redundancy feature.
explains the various types of circuits used.
FUNCTIONAL OPERATION
The primary function of the RIO is to allow the MFP to interface
with remote slave modules. Its secondary function is to provide
the MFP with additional Digital Indicator Station (DIS) links.
The RIO also supports Analog Control Station (ACS) links. The
MFP communicates with the Remote Master Processor (RMP)
over the Expander Bus. The RMP communicates with Remote
Slave Processors (RSPs) over a serial link at a rate of 1 Mbit/
second and uses Cyclic Redundancy Check (CRC) error check-
ing. IMRIO02 also supports Network 90 Multi-Function Con-
trollers (MFC).
PHYSICAL OPERATION
Upon start-up, the Multi-Function Processor downloads the
control configuration to the shared memory of the local RMP.
The RMP allocates its shared memory accordingly and sends a
copy of the configuration to the RSPs. The RSPs are master
modules on their remote Expander Buses, reading and writing
data to their slave modules. They receive data from the RMP
and transmit data back upon request. When the communica-
tion link is established, the MFP reads and writes data directly
to the shared memory of the RMP. the age of data is propor-
tional to the number of expander bus slaves on the link, and
the number of RSPs.
Security
Module security is provided by a Machine Fault Timer (MFT)
and a Bus Fault Timer (BFT). The MFT is reset regularly by the
microprocessor under normal operation. If the MFT expires, all
critical parts of the module will be reset. The BFT is usually
reset by the bus clock and has 2 modes of operation.
1.
Remote Master Processor
. When the RIO is used at the
local end, it is a slave to the MFP. The BFT will expire if the bus
clock stops for more than 10 milliseconds. The RSPs are
informed and in turn put their slaves in a “Fail Safe Mode”. In
this mode, the modules hold their current configurations until
