Design implications

Process control
Overview | Backup & recovery | Contingency planning | Other

Overview

In implementing a process control system, several special factors need to be considered.
These are brought about due to controlling real-time events, and the downstream effect of a system failure.

For example,
a watering system that doesn't come on when the plants are dry will result in plants that are stunted or possibly dead.

Backup and recovery

Backup - what happens in the event of failure

failsafe if controller broken, heater shut it down or turned to preset level ?
traffic light fail - flash red ?
Un-interruptable power supplies (UPS)

Contingency planning

Planning for the unusual

Electrical failure
Natural disasters (Storms, earthquake)
Human interaction

Other

Safety features
manual overrides
Positioning of sensors and controllers
Managing minor-faults (eg. Sensor failure) - auto dialup
Parallelism

[Rev: 28/1/98] Jun-97 © 1997-98 V/2-Com (Verhaart), P O Box 8415, Havelock North, New Zealand.