Rotronic AG
Bassersdorf, Switzerland
HygroFlex HF7 Humidity Temperature
Transmitters: User Guide
HygroFlex HF7
Humidity Temperature Transmitters
User Guide
© 2009-2011; Rotronic AG E-M-HF7-V1_24
Rotronic AG
Bassersdorf, Switzerland
HygroFlex HF7 Humidity Temperature
Transmitters: User Guide
Table of contents
1 Overview .............................................................................................................................................. 3
2 Mechanical configurations and dimensions ..................................................................................... 4
3 General description ............................................................................................................................. 5
3.1 Power supply .................................................................................................................................... 5
3.2 Measured parameters ...................................................................................................................... 5
3.3 Calculated parameters ..................................................................................................................... 5
3.4 Analog output signals ....................................................................................................................... 5
3.5 Display option ................................................................................................................................... 6
3.6 Service connector ............................................................................................................................. 6
3.7 Sensor protection (dust filter)............................................................................................................ 7
4 User configurable settings and functions ......................................................................................... 7
4.1 Function overview ............................................................................................................................. 7
4.2 Factory default settings .................................................................................................................... 8
5 Mechanical installation ....................................................................................................................... 9
5.1 General guidelines ............................................................................................................................ 9
5.2 Enclosure installation (HF7 type N and W) ..................................................................................... 10
5.3 Probe installation (HF7 type N, D and A) ........................................................................................ 10
6 Electrical installation ........................................................................................................................ 11
6.1 General wiring guidelines ............................................................................................................... 11
6.2 Cable grip and cable specifications ................................................................................................ 12
6.3 Wiring and terminal block diagrams ................................................................................................ 12
7 Operation ........................................................................................................................................... 16
7.1 Minimum load requirements for the HF73 with voltage outputs ...................................................... 16
7.2 HF72 and HF73 transmitters (analog outputs)................................................................................ 16
8 Maintenance....................................................................................................................................... 17
8.1 Service cable .................................................................................................................................. 17
8.2 Location of the service connector (mini USB type) ......................................................................... 17
8.3 Periodic calibration check ............................................................................................................... 18
8.4 Cleaning or replacing the dust filter ................................................................................................ 18
8.5 Validation of the output signals transmission .................................................................................. 18
9 Firmware updates .............................................................................................................................. 19
10 Technical data ................................................................................................................................... 20
10.1 Specifications ................................................................................................................................. 20
10.2 Dew point accuracy ........................................................................................................................ 22
11 Accessories ....................................................................................................................................... 23
12 Supporting documents ..................................................................................................................... 23
13 Document releases ........................................................................................................................... 23
© 2009-2011; Rotronic AG E-M-HF7-V1_24
Rotronic AG
Bassersdorf, Switzerland
HygroFlex HF7 Humidity Temperature
Transmitters: User Guide
Applicability:
This manual applies to all instruments of the HF7 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 HF7 transmitter series are designed for fixed installation in industrial applications. The HF7 measures
relative humidity and temperature and can be configured to calculate the dew or frost point. Depending on the
model, the HF7 can measure environments within the range of 0 to 100 %RH and -100 to 150 C (-148 to
302 F). The electronics operating range is limited to -50…100 °C (-58…212 °F)
Two types of electronic circuit are available:
HF72: 2-wire, loop powered (4…20 mA current signal)
HF73: 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 and can be used to measure humidity only, temperature
only or both parameters.
The HF7 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 HF7 series offers the following 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
Fail safe mode
Data recording
The ability for the user to easily update the AirChip 3000 firmware means that instruments of the HF7 series
can be kept up-to-date regarding any future functionality improvement.
© 2009-2011; Rotronic AG E-M-HF7-V1_24
Rotronic AG
Bassersdorf, Switzerland
HygroFlex HF7 Humidity Temperature
Transmitters: User Guide
2 Mechanical configurations and dimensions
© 2009-2011; Rotronic AG E-M-HF7-V1_24
Rotronic AG
Bassersdorf, Switzerland
HygroFlex HF7 Humidity Temperature
Transmitters: User Guide
3 General description
3.1 Power supply
Depending on the circuit type, the HF7 requires the following power supply:
a) HF72 (2-wire, loop powered): 10…28 VDC - depending on the load connected to the output(s). The
minimum supply voltage can be determined as follows:
V min = 10 V + (0.02 x Load*) *Load resistance in ohms.
For the maximum load of 500 , the minimum supply voltage is 10 + (0.02 x 500) = 20 VDC. With both
output circuits closed, the maximum current consumption is 40 mA.
b) HF73 (3-wire with analog outputs): 15 to 40 VDC (see note below) or 12 to 28 VAC. With both output
circuits closed, the maximum current consumption is 50 mA.
Note: depending on the type of output signal, the HF73 will operate with the following minimum voltage
0…1 V outputs: 5 VDC or 5 VAC
0…5 V outputs: 10 VDC or 8 VAC
0…10 V outputs: 15 VDC or 12 VAC
0…20 mA or 4 …20 mA outputs: 6 VDC or 5 VAC with 0 load
15 VDC or 12 VAC with 500 load
3.2 Measured parameters
The HF7 measures relative humidity with a ROTRONIC Hygromer® IN1 capacitive sensor and temperature
with a Pt100 RTD.
3.3 Calculated parameters
Using the ROTRONIC HW4 software, the HF7 can be configured by the user to calculate either the dew point
or the frost point.
3.4 Analog output signals
HF72 and HF73
With the ROTRONIC HW4 software any of the two analog output signals can be made to correspond to one of
the following:
Relative humidity
Temperature
Dew or frost point
Any output can also be disabled.
The scale of each analog output can be set within the numerical limits of -999.99 and 9999.99.
The D/A converters used to generate the analog output signals feature a 16-bit resolution.
The D/A converters used to generate the analog output signals feature a 16-bit resolution and exhibit a small
positive offset at the bottom of the signal range as indicated below:.
© 2009-2011; Rotronic AG E-M-HF7-V1_24
Rotronic AG
Bassersdorf, Switzerland
HygroFlex HF7 Humidity Temperature
Transmitters: User Guide
Maximum offset at range bottom
HF73
The ROTRONIC HW4 software allows changing the type of output signal to one of the following: 0…20 mA,
4…20 mA, 0…1V, 0…5V or 0…10V. Both output signals are automatically configured with the same signal
type. No calibration or adjustment is required after changing the type of output signal.
In the case of voltage output signals, load requirements apply to the external device or circuit connected to the
HF73 transmitter. These requirements are defined in the “Operation” chapter
3.5 Display option
The upper line of the display corresponds to relative humidity or dew / frost
point and the bottom line corresponds to temperature.
The display can be configured to show a trend indicator on each line:
▲: increasing value
▼: decreasing value
In the event of an alarm the display shows the symbol [ ! ] to the right of the value. For instructions see the
following HW4 manual: E-M-HW4v3-F2-007.
The display option for the HF73 has a backlight. The display option for the HF72 does not have a backlight
3.6 Service connector
The service connector is a UART digital interface (Universal Asynchronous Receiver Transmitter) with a miniUSB type connector. This allows connecting the HF7 either to a PC running the ROTRONIC HW4 software or
to a probe input of another instrument that is compatible with the HygroClip 2 (HC2) probes. In both cases a
service cable is required. See “Maintenance” for the location of the service connector and for the type of
service cable to be used.
Connecting the HF7 to a PC is used to configure the HF7, gain access to the HF7 functions such as
humidity and temperature adjustment, read data from the HF7 on the PC and update the AirChip 3000
firmware.
Connecting the HF7 to the probe input of another instrument is useful only when the other instrument has
its own display and keypad, and has an internal menu equivalent to the menu of the HP23 hand-held
calibrator. The connection allows showing the data measured by the HF7 on the other instrument display
and also allows using the other instrument internal menu to do for example a humidity and temperature
adjustment of the HF7.
© 2009-2011; Rotronic AG E-M-HF7-V1_24
Rotronic AG
Bassersdorf, Switzerland
HygroFlex HF7 Humidity Temperature
Transmitters: User Guide
MEASUREMENT ACCURACY AND RELIABILITY
► Humidity / temperature adjustment
o 1-point or multi-point humidity calibration or adjustment
o 1-point or 2-point temperature calibration or adjustment
o Generate a time stamp for calibrations and adjustments
o Retain and view last adjustment date and adjustment values
o Generate calibration and adjustment protocols
► Automatic humidity sensor test
and optional drift compensation
Tests the humidity sensor for drift caused by contaminants and
can be used to automatically apply a correction. The test is
automatically carried out at regular intervals of time. Can be
configured, enabled, or disabled
The humidity sensor status can be verified either with the HW4
software or with the instrument display (if available) and is
shown as Good, SQ-tuned (corrected for drift) or Bad (defective)
The data recording function differs from a true data logging
function in the sense that the AirChip 3000 does not time stamp
the data. This data recording function can be used to investigate
events such as a sensor malfunction as well as to retrieve data
that would otherwise be lost
o Start or stop data recording - up to 2000 value pairs (%RH
and temperature). Starting a recording session erases all
previously recorded data
o The recording mode and log interval can be specified
o When the device is powered off, the recording session is
paused but not ended As long as the recording session has
not been ended, the device automatically resumes recording
data when powered up again
o The recorded data can be downloaded to a PC with the
HW4 software, time stamped and viewed
3.7 Sensor protection (dust filter)
A dust filter is required to protect the sensors against dust particles and high air velocity. The probe of the HF7
is equipped with a with a metal filter base mod. NSP-ME. The filter cartridge must be ordered separately (see
Accessories 11.5). Filter cartridge mod. SP-M15 is suitable for most applications.
4 User configurable settings and functions
The HF7 ships configured as specified on the customer order. The analog outputs can be used just as with
any conventional humidity and temperature transmitter and most users will never need to use the HF7
configurable settings and functions.
Making use of the HF7 configurable settings and functions is entirely up to the user and the appropriate
settings depend on the user application. We have provided below a short description of the HF7 functions and
also indicated the factory default settings.
4.1 Function overview
© 2009-2011; Rotronic AG E-M-HF7-V1_24