Oil and gas production handbook An introduction to oil and gas production

Typical process control system 
 
 Process control systems consist of the following components: 

---

101 
 
 
•  Field instrumentation: sensors and switches that sense process 
conditions such as temperature, pressure or flow. These are 
connected over single and multiple pair electrical cables 
(hardwired) or communication bus systems called fieldbus. 
•  Control devices, such as actuators for valves, electrical switchgear 
and drives or indicators are also hardwired or connected over 
fieldbus. 
•  Controllers execute the control algorithms so that the desired actions 
can be taken. The controllers also generate events and alarms 
based on changes of state and alarm conditions, and prepare data 
for operators and information systems. 
•  A number of servers perform the data processing required for data 
presentation, historical archiving, alarm processing and engineering 
changes. 
•  Clients, such as operator stations and engineering stations, are 
provided for human interfaces to the control system. 
•  The communication can be laid out in many different configurations, 
often including connections to remote facilities, remote operations 
support and other similar environments.