|
|
PLC |
DCS |
| Market Intorduction |
1960’s |
1970 |
| Replacement of…. |
Electromechanical Relays |
Pneumatic & Single-Loop Controllers |
| Products Manufactured… |
“Things” |
“Stuff” |
| Classic Application |
Automotive |
Refining |
| Type of Control |
Discrete |
Regulatory |
| Redundancy |
“Warm” Backup |
“Hot” Backup |
| Engineering Mindset |
“Programming” |
“Configuration” |
| Operator interaction |
Exception Basis |
Man in the Loop |
| Operator interaction |
Exception Graphics |
Sophisticated Graphics |
| Size/Foodprint |
Compact |
Large |
| Up-front cost |
$$ |
$$$$ |
| System |
“open” |
“Closed (proprietary)” |
| Programming Language |
High level programming languages are available for creating custom logic |
Custom logic created from existing function blocks |
| Algorithms |
Customized routines usually required- |
Many algorithms (i.e. PID) are complex and do not vary among application |
| Standard libraries |
Standard libraries considered nice features |
Standard application libraries are expected (function blocks and faceplates) |
| Solutions |
Provisions must be available to integrate functions/ products into an integrated architecture |
Entire system is expected to function as a Complete solution |
| Redudancy |
Redundancy may not be cost justified |
System redundancy is often required |
| Analog Control |
Analog Control: Simple PID only |
Analog Control: Simple to advanced PID control up to Advanced Process Control |
| Diagnostics |
Diagnostics to tell you when something is broken |
Asset Management alerts you to what migh break before it does |
| Design |
System
designed to be flexible |
System designed to make it”easy” to engineer process applications |
