Watlow EZ-ZONE
®
PM Integrated Controller • 115 • Chapter 10 Applications
With the release of version 7.00 firmware several new
functions were added to the EZ-ZONE PM family of
controls. This chapter contains some sample applica-
tions using these new functions.
Example 1: Single Loop Control
Requirements:
One input is required and at least one output adjusts
the controlled part of the process.
Overview:
Controls one process value to a user entered Closed
Loop Set Point based on an control algorithm.
Control loop 1 will control Analog Input 1 to Closed
Loop Set Point 1.
Example 2: Sensor Backup
Requirements:
Two analog inputs and the enhanced software option
are required and at least one output adjusts the con-
trolled part of the process.
Overview:
The Sensor Backup feature controls a process based
on a primary sensor on Analog Input 1. If this sensor
fails, then the process is controlled based on the sec-
ondary sensor on Analog Input 2.
When function is set for Sensor Backup, the PV Func-
tion output equals Source A if sensor of Analog Input 1
reading is valid or Source B if sensor reading is invalid.
Control loop 1 will control the valid Analog Input sensor
to Closed Loop Set Point 1.
Example 3: Square Root
Requirements:
One analog input and the enhanced software option
are required and at least one output adjusts the con-
trolled part of the process.
Overview:
Calculates the square root value of the sensor connect-
ed to Analog Input 1.
When function is set for Square Root, the PV Function
output equals square root value of Source A. Control
loop 1 will control Analog Input 1 to Closed Loop Set
Point 1.
Example 4: Ratio
Requirements:
Two analog inputs and the enhanced software option
are required and at least one output adjusts the con-
trolled part of the process.
Overview:
The Ratio feature allows control of one process as a
ratio of another process. This is especially useful in
applications that mix two materials, whether steam,
paint or food ingredients. Analog Input 1 monitors the
controlled part of the process. Analog Input 2 of the
controller measures the part of the process that is ei-
ther uncontrolled or controlled by another device. The
part of the process controlled will be maintained at a
level equal to the quantity measured at input 2 mul-
tiplied by the ratio term set by the user as Closed Set
Point 1.
Control Loop 1
Single Loop Control
Closed Loop
Set Point 1
Heat Algorithm
Cool Algorithm
Analog Input 1
Source A
Heat Power
Cool Power
Heat
Cool
0 to 100%
0 to 100%
Output n
Output n
Sensor Backup
Closed Loop
Set Point 1
Function
Filter
Source A
Source A
Source B
Heat Power
Cool Power
0 to 100%
0 to 100%
Output
Heat
Cool
Output n
Output n
Analog Input 1
Analog Input 2
Control Loop 1
PV Function
Square Root
Closed Loop
Set Point 1
Function
Filter
Source A
Source A
Heat Power
Cool Power
0 to 100%
0 to 100%
Output
Heat
Cool
Output n
Output n
Analog Input 1
Control Loop 1
PV Function
Chapter 10: Applications
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