When Should You Use Cascade Control?

Cascade control has many potential benefits:

1. It will catch certain load changes sooner and correct for them faster.
2. It will effectively linearize the secondary variable.
3. It can and should shorten the natural period of the primary loop.
4. Some instrumentation tricks can be played.

For more information on these subjects and others you may refer to a booklet "Controller Tuning and Control Loop Performance, a Primer" , which is available in the US for $17, postpaid if prepaid. It has sold 29,740 copies to date. Control Engineering Magazine has referred to it as "PID Without the Math".

Information may be found at

If you wish, I could e-mail you the same information.

David W. St. Clair Straight-Line Control Co.