Chapter 4 System Operation; System Overview; Communications; Redundancy - GE PACSystems RX3i User Manual

Chapter 4 System Operation

This chapter provides a System Overview and describes:
•

Communications

•

Redundancy

•
I/O Scans
•
Alarms
•
Station Manager

4.1 System Overview

4.1.1 Communications
The EIS001 is a self-standing communication processor. During normal operation, it handles
asynchronous requests from its IEC 104 Client and exchanges corresponding data with the host RX3i
CPU at designated portions of the CPU scan. It performs all of these tasks without burdening the CPU
beyond the windows designated for data exchange.
On power-up or reset it will await the COMMREQ from the user application environment to set
parameters and put it into operation. Once it receives the parameters, the module scans the RX3i for
data, based on its configuration. It detects and registers data changes within its host Controller. It
also services asynchronous IEC 104 Client requests for polling (such as reading of Controller data)
and writing of data to Controller memory.
Because the module is self-standing, it polls the CPU during the CPU background scan window for
data, per its configuration. The module detects and records all corresponding data changes
internally. Whenever a Client writes to it, the module must wait for the CPU to allow it to write the
corresponding information into the Controller memory during the same window.
All Ethernet traffic is asynchronous to the RX3i CPU scanning operation, so the module can service
many different requests without burdening the CPU with processing them.
4.1.2 Redundancy
There are no restrictions that apply to an EIS001 when installed in a redundant RX3i CPU. The polling
of event and integrity data will occur as if it were in a simplex system.
The EIS001 is capable of taking advantage of the Redundant IP feature of a Redundant CPU system,
allowing two EIS001 modules in two racks to appear as one module.
Note: The Write Operations and ADSU will be processed by the active controller only.
Note: A Client connected to an RX3i CRU system that uses Redundant IP can experience a bump, or
loss of communication in the event of a role switch at the IEC 104 Client station. This is mainly
due to the way the Client and its host Operating system processes the change in end station
whenever the RX3i switches roles. The Client application, as well as the RX3i Controller
application must be developed to withstand a likely bump in the connection during a role
switch and not act inappropriately. This depends on the client tolerance and AUP File
parameters (wkal_idle, wkal_cnt, wkal_intvl) needs to be adjusted depending on the
network hops to get an optimized performance for role switch operation.
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