Watlow Series 988 - Manual (Page 149)

9.12 WATLOW Series 988 User’s Manual Enhanced Software Features, Chapter 9
Enhanced Software
Ratio
Requirements
Ratio control requires enhanced software. Two analog inputs are required
to monitor the process, and at least one output adjusts the controlled part
of the process.
Overview
This feature allows the Series 988 to control one process as a ratio of
another process. This is especially useful in applications that mix two
materials, whether steam, paint or food ingredients.
Input 2 of the controller measures the part of the process that is either
uncontrolled or controlled by another device. The part of the process con-
trolled by the 988 will be maintained at a level equal to the quantity mea-
sured at input 2 multiplied by the ratio term set by the user. Input 1 mon-
itors the controlled part of the process.