Full Description

The standardization of control concepts and hardware can be advantageous in the operation and maintenance of HVAC systems, especially in facilities consisting of large numbers of buildings. One possible approach toward standardization of control components and logic would be to adopt the use of single-loop digital controllers (SLDCs). Predominantly used by the process control industries, single-loop digital controllers are suitable for a variety of HVAC control applications.

Single-loop digital controllers typically receive one analog input and provide one analog output. Most are fully configurable in that the input span, display units, control mode (P, PI, PID), control action, and tuning constants can be entered by the end user making them interchangeable between applications. Many offer automatic/manual control and a self-tuning feature. Other advantages are that they are widely available and of industrial grade.

This paper reviews performance features and specifications of a number of these controllers and some basic applications are presented. In addition, two types of self tuning algorithms are discussed and the methods by which they are applied.

Units: Dual

Citation: Symposium, ASHRAE Transactions, 1988, vol. 94, pt. 2, Ottawa

Product Details

Published: 1988 Number of Pages: 10File Size: 1 file , 1 MB Product Code(s): D-OT-88-18-4