Watlow Electric 989 Manual Do Utilizador

WATLOW Series 988 User’s Manual

Enhanced Software Features, Chapter 9

Enhanced Software

Sample Application
Blue pigment must be added to paint at a ratio of one part per 100 to cre-
ate a mixed paint of the desired color. The uncolored paint flows into the
mixer in an uncontrolled stream that is set manually and sensed by input
2. A motorized valve controls the flow of pigment, which is monitored by
the flow sensor to input 1. The flow rate of the uncolored paint determines
the set point for the motorized valve that controls the pigment flow. If an
operator needs to change the rate of flow for the uncolored paint, the set
point will shift accordingly to maintain the correct ratio in the mixing
tank.

The application engineer set up this feature in software by choosing ratio
[rAti] as the control [CntL] parameter in the Global Menu. The set point
value displayed was then a ratio value. He entered 0.01 to maintain an
input 1:input 2 ratio of 1:100.

input 1

input 2

output 1

controlled flow 
of pigment

flow 

transmitter

motorized 
valve

flow 

transmitter

mixed paint

uncontrolled 
flow of 
unmixed paint