Honeywell HC900 - Redundant Operating Characteristics; Start-Up; Modes of operation (Figure 83)

Function Blocks
ENTH Humidity and Enthalpy Function Block
Revision 11 HC900 Hybrid Control Designer Function Block Reference Guide 153
2/07
ENTH Humidity and Enthalpy Function Block
Description
The ENTH label stands for Humidity and Enthalpy. This block is part of the Calculation category.
Function
This block calculates the Absolute Humidity and Enthalpy based on the input Air temperature (X1), Air
relative Humidity (X2) and Barometric Pressure (P3). This block does not have any configurable
parameters. ERR pin turns ON when any of the inputs (X1, X2, P3) or outputs (Y1, Y2) are out of range. In
case of ERR ON, outputs Y1 and Y2 are set to 0.0.
Inputs
X1
= Air temperature in degrees F. Range is 23 – 122 degrees F.
X2 = Air relative humidity in % RH. Range is 0 – 100% RH.
P3 = Barometric Pressure in psi. Range is 0 – 146 psi. When this is not connected the default value is 14.7
psi.
Outputs
Y1
= Enthalpy (0 to 100 Btu/lb)
Y2 = Absolute humidity (0 to 100lb/lb)
ERR = ON when any input or output is out of range. Outputs Y1 and Y2 are set to 0.0.
Configurable Parameters
This block has no configurable parameters.