Appendix A: Application Examples A.3 Furnace Pressure Control with 3-State Pulse Output
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A.3 Furnace Pressure Control with 3-State
Pulse Output
Description
This example shows how to control the pressure in a steam boiler furnace with a
draught valve motor at the flue duct. High and low pressure alarms are required
at 0.000 kPa and +0.500 kPa respectively.
Definition of Control Problem
The object is to control the furnace pressure as shown in the figure below. The
valve motor M is of the increase/decrease type and has position feedback in the
form of a potentiometer (Pot) on the valve. The pressure is measured by the
transducer PT1. An ECA60 or an ECA600 can be used to solve this problem.
Figure 5 Furnace Pressure Controlled by a Draught Valve.
Mechanical Installation
Please refer to chapter 2 of this manual for details of the mechanical installation.
Preset Configuration
None of the preset configurations match our requirements exactly so we will start
with the Default Setup and modify that.
Draught valve
Furnace
PICA1
PT1
M
Pot
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