Watlow ez-zone pm - Example 8: Vaisala

Watlow EZ-ZONE
®
PMI Controller • 222 • Chapter 10 Applications
Example 8: Vaisala
Requirements: Two analog inputs and the enhanced software option are required and at least two
outputs adjusts the controlled temperature and humidity processes.
Overview:
Vaisala Model HMM-30C Solid-state Relative Humidity Sensor is supported with the Vaisala congu-
ration. Analog Input 1 is used to measure temperature and Analog Input 2 must be a process input
connected to a Vaisala sensor. The controller provides temperature compensation for the Vaisala
sensor. The humidify and dehumidify outputs are disabled when Analog Input 1 temperature falls
below -40 F/- 40 C, or goes above 320 F/160 C. When function is set for Vaisala, the PV Function
output equals the calculated relative humidity compensated by the sensor on Analog Input 1.
Vaisala
Set Point 2
Set Point 1
Function
Filter
Source A
Source A
Source B
Source A
Heat Power
Heat Power
Cool Power
Cool Power
0 to 100%
0 to 100%
0 to 100%
0 to 100%
Output
Heat
Heat
Cool
Cool
Output n
Output n
Output n
Output n
Analog Input 1
Analog Input 2
Control Loop 2
Control Loop 1
PV Function
Temperature
Humidity