Dewp Function Block - Honeywell UMC800 Reference Manual

2.18 DEWP Function Block

Description
The DEWP label stands for Dewpoint Calculation. This block is part of the Calculations category. It looks
like this graphically on the Control builder.
Function
Monitors Dewpoint or Carbon Potential, or uses a Zirconia Probe sensor input to supply a Dewpoint PV to
a PID function block for Dewpoint control. Use in conjunction with other blocks including a PID to
generate more elaborate control strategies than that provided by the Carbon potential (CARB) function
block.
Inputs
Probe = Oxygen Sensor Input from AI (0-2 mV)
TEMP = Temperature Input (°F or °C) from AI Input
%CO = Percent Carbon Monoxide Input 1 - 100%
Outputs
DEWPT = Calculated Dewpoint Output
%C = Calculated Percent Carbon Output
SPHLIM = Control Setpoint High Limit for Anti-soot.
WRLIM = Command to write the setpoint high limit.
LOTEMP = ON when TEMP is <= calculated low temperature dropoff.
Block Properties
Double click on the function block to access the
function block properties dialog box.
Block Order (Read Only)
You can change the assigned execution order
number by selecting "Execution Order" in the
"Configure" menu and arrange the order to suit
your control strategy.
Configuration Parameters
You must configure the DEWP function Block
parameters to the desired value or selection that
matches your operating requirements.
Table 2-19 describes the parameters and the
value or selection.
3/99 Function Block Reference Guide
Function Blocks
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