Honeywell UMC800 Reference Guide

Function Blocks
Function Block Reference Guide 3/99156
2.50 PID Function Block,
continued
2.50.4 Example 4 - Ratio Control
The RATIO control loop requires selection of the
remote SP of the PID for ratio control. The Ratio
and Bias values are available for adjustment
from the Control Setup screen of the Operator
Interface. The Bias may be a local value or come
from an external source such as an O2 analyzer
trim arrangement. You may elect to use % for
the ratioed inputs (typically for boiler
applications) or Eng. Units (EU) (for feed flows to
a reactor, for example).
External Bias
Input
Air (controlled variable)= Ratio x Fuel (RSP, or wild variable) + BIAS
Figure 2-50 Ratio Control Example
Continued next page

Honeywell UMC800 Specifications

General

Brand	Honeywell
Model	UMC800
Category	Controller
Language	English