ROTRONIC HF3 - Manual (Page 3)

E-M-HF3-V1_22
Rotronic AG
Bassersdorf, Switzerland
Document code Unit
HygroFlex HF3 Transmitters and Thermo-
hygrostats: User Guide Instruction Manual
Document Type
Page 3 of 27
Document title
© 2009-2011; Rotronic AG E-M-HF3-V1_22
Applicability:
This manual applies to all instruments of the HF3 series with firmware version 1.x, where 1.x can be 1.0, 1.1,
etc. Changes to the last digit of the version number reflect minor firmware changes that do not affect the
manner in which the instrument should be operated.
1 Overview
The HF3 transmitters and thermo-hygrostats measure temperature, relative humidity and the dew or frost
point. The HF3 series is designed for fixed installation in cost sensitive HVAC applications where conditions
are within the range of 0 to 100 %RH and -40 to 60 C (-40 to 140 F).
The HF3 features well proven sensors and a robust housing. Digital signal processing ensures consistent
product performance and also facilitates the task of field maintenance with features such as potentiometer
free - digital calibration.
Based on the ROTRONIC AirChip 3000 digital technology, the HF3 series offers the following user functions:
User configurable settings
Calculation of the dew or frost point
Humidity temperature calibration and adjustment
Simulator mode
Automatic humidity sensor test and drift compensation
Sensor failure mode
Data recording
The ability for the user to easily update the AirChip 3000 firmware means that instruments of the HF3 series
can be kept up-to-date regarding any future functionality improvement.
HF3 transmitters: two types of electronic circuit are available: HF32: 2-
wire, loop powered (4…20 mA current
signal) and HF33: 3-wire (voltage or current signal). Both circuit types provide linear analog outputs signals for
transmission over a length of cable to a remote display, recorder, controller or data processing unit. The HF3
transmitters can be used to measure humidity only, temperature only or both parameters.
HF3 thermo-hygrostats: the HF34 (3-wire circuit type) is available as a thermo-hygrostat (humidity and
temperature), as a thermostat (temperature only) or as a hygrostat (humidity only).