Rotronic HygroFlex 1 User manual

HygroFlex
Humidity Temperature Transmitter
Instruction Manual

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Contents
Overview........................................................................................................................................3
General Description........................................................................................................................4
Power Requirements..................................................................................................................4
Probes and Probe Inputs ............................................................................................................5
Analog Outputs (HygroFlex 1 and HygroFlex 3).........................................................................7
RS232 Digital Port......................................................................................................................8
HW3 Software ............................................................................................................................8
RS485 Networking (HygroFlex 2 and HygroFlex 3).....................................................................8
Unit System................................................................................................................................9
Optional Display and Keypad......................................................................................................9
Keypad.......................................................................................................................................9
Installation....................................................................................................................................10
Mechanical Installation .............................................................................................................10
Electrical Installation.................................................................................................................12
Network Configuration and Wiring (HygroFlex 2 and HygroFlex 3)............................................16
Configuration of the Analog Outputs .........................................................................................17
Functions .....................................................................................................................................17
CALCULATE (HygroFlex 2 and HygroFlex 3)............................................................................18
DISPLAY (HygroFlex 2 and HygroFlex 3) .................................................................................19
ADJUST M.PT (2- to 4-point adjustment against a reference environment) ...............................19
ADJUST 1PT (1-point adjustment against a reference environment).........................................21
ADJUST REF (1-point adjustment against a reference probe)...................................................22
PROBE ....................................................................................................................................22
RS STATUS.............................................................................................................................23
SYS STATUS...........................................................................................................................23
Calibration with a HygroPalm Indicator .........................................................................................24
Display the Transmitter Measurements.....................................................................................25
Functions (except ADJUST M.PT and ADJUST 1PT)................................................................25
Functions ADJUST M.PT and ADJUST 1PT.............................................................................25
Function ADJUST REF.............................................................................................................25
Environmental Limits....................................................................................................................26
Maintenance.................................................................................................................................26
On-Site Maintenance................................................................................................................26
Factory / Metrology Lab. Maintenance ......................................................................................26
Specifications...............................................................................................................................27
Appendix 1: Practical Advice for Measuring Humidity....................................................................29
Appendix 2: Resolution of the Analog Signals...............................................................................29
Appendix 3: Maintenance of the ROTRONIC probes.....................................................................30
Cleaning or Replacing the Dust Filter of the Probe....................................................................30
Periodic Calibration Check of the Probes..................................................................................30
Appendix 4: Calibration Basics .....................................................................................................31
Temperature Calibration...........................................................................................................31
Humidity Calibration..................................................................................................................31
Appendix 5: Humidity Definitions ..................................................................................................33
Appendix 6: Dew Point Accuracy..................................................................................................35
Appendix 7: RS232 Communication Protocol................................................................................36
Note: functions such as instrument configuration with a PC as well as the calibration of
HygroClip probes with a PC require the optional HW3 software. Instructions for using the
HW3 software are not included in this manual. These instructions are shipped separately on
the same CD ROM as the HW3 software.

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Overview
The HygroFlex is a series of 3-wire humidity temperature transmitters that is available with a wide
variety of probes for use in many different industrial and scientific applications. The HygroFlex
series uses a micro-processor based design to achieve unparalleled accuracy, reliability and
versatility.
The HygroFlex is available in 3 different models:
HygroFlex 1: basic industrial transmitter with analog outputs
relative humidity and temperature
-compatible with any ROTRONIC HygroClip digital probe 1)
-relative humidity and temperature analog outputs
-test connector for communication with the HygroPalm indicator 2)
-software-based calibration (HygroClip probes only)
-internal service connector (RS232) for configuration with PC (units, ranges)
-two linearized analog outputs, signal type (mA, V) configurable by means of jumpers 3)
-optional LC display and keypad 4)
1) ROTRONIC analog probes are also accepted with some restrictions
2) allows the HygroPalm to read the transmitter or to calibrate a digital probe
3) 0..1V, 0..5V, 0..10V, 0..20 mA, 4..20 mA
4) allows direct calibration of digital probes by the transmitter and direct access to other functions
HygroFlex 2: fully digital, networkable industrial transmitter
relative humidity, dew point (or other) and temperature
-compatible with any ROTRONIC HygroClip digital probe 1)
-optional analog input for second probe 2)
-relative humidity, temperature, dew point, wet bulb, mixing ratio, enthalpy, etc 3)
-test connector for communication with the HygroPalm indicator 4)
-software-based calibration (HygroClip probes only)
-RS232 and RS485 digital ports 5)
-optional LC display and keypad 6)
1) ROTRONIC analog probes are also accepted with some restrictions
2) pressure probe or ROTRONIC HygroClip digital probe – some restrictions apply
3) uses either a fixed barometric pressure value or the measurements from an analog pressure probe
for those parameters that require pressure as a computational input. The fixed pressure value can be
changed with the optional HW3 software.
4) allows the HygroPalm to read the transmitter or to calibrate a digital probe
5) The computed parameter (dew point or other) is not sent to these ports. Use of the HW3 software on
a PC allows real time computation of the dew point (or other) and facilitates both networking and
instrument configuration
6) allows direct calibration of digital probes by the transmitter and direct access to other functions

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HygroFlex 3: analog / digital, networkable industrial transmitter
relative humidity, dew point (or other) and temperature
-compatible with any ROTRONIC HygroClip digital probe 1)
-optional input for second probe 2)
-relative humidity, temperature, dew point, wet bulb, mixing ratio, enthalpy, etc 3)
-test connector for communication with the HygroPalm indicator 4)
-software-based calibration (HygroClip probes only)
-RS232 and RS485 digital ports 5)
-three linearized analog outputs, signal type (mA, V) configurable by means of jumpers 6)
-optional LC display and keypad 7)
1) ROTRONIC analog probes are also accepted with some restrictions
2) pressure probe or ROTRONIC HygroClip digital probe – some restrictions apply
3) Uses either a fixed barometric pressure value or the measurements from an analog pressure probe
for those parameters that require pressure as a computational input. The fixed pressure value can be
changed with the optional HW3 software.
4) allows the HygroPalm to read the transmitter or to calibrate a digital probe
5) The computed parameter (dew point or other) is not sent to these ports. Use of the HW3 software on
a PC allows real time computation of the dew point (or other) and facilitates both networking and
instrument configuration
6) 0..1V, 0..5V, 0..10V, 0..20 mA, 4..20 mA - corresponding to relative humidity, temperature and
computed parameter (or relative humidity of second probe)
7) allows direct calibration of digital probes by the transmitter and direct access to other functions
General Description
Power Requirements
The HygroFlex is available with a choice of two basic internal power modules:
-standard power module for operation with 12 to 35 VDC (maximum 300 mA) or with 12 to 24 VAC.
-optional power module for operation with voltages within the range of 90 to 264 VAC (50/60 Hz).
HygroFlex 1 HygroFlex 2 HygroFlex 3

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Probes and Probe Inputs
Model HygroFlex 1 HygroFlex 2 HygroFlex 3
number of probe inputs 11 (standard) or 2 (optional)
probe types (see below) ROTRONIC Digital
ROTRONIC Analog ROTRONIC Digital ROTRONIC Analog
Third-Party Analog
number of digital input channels 11 (input 1) + 1 (input 2 - optional)
number of analog input channels 22 (input 1) + 1 (input 2 - optional)
analog input A/D resolution 10-bit 10-bit
Unless otherwise specified when ordering, all probe inputs are factory programmed to accept a HygroClip
digital probe. Prior to using any analog probe, the corresponding input should be re-programmed. This can be
done with the HW3 software after connecting the RS232 port to a PC (see separate HW3 manual). Probe
input 1: accepts either a ROTRONIC HygroClip digital probe or a ROTRONIC analog probe with adapter
cable. Probe input 2: accepts either a 1-channel third-party analog probe (for example a pressure probe) or a
second ROTRONIC HygroClip digital probe with adapter cable.
HygroClip Digital Probes
The HygroFlex is primarily designed for use with the ROTRONIC HygroClip digital humidity
temperature probes. These probes permit to take full advantage of all the features and functions of
the HygroFlex such as the software based calibration.
The ROTRONIC HygroClip digital probes are highly accurate and are calibrated entirely by means
of software (no adjustment potentiometers). Because calibration and other data are stored in the
probe non-volatile memory, the probes are fully interchangeable. When a probe requires calibration
or has to be repaired, it can be replaced with another probe in a few seconds. The ROTRONIC
HygroClip digital probes are available in different configurations so as to meet the requirements of
each application: HygroClip IW
for surface mount (area monitoring)
max. 85°C (185°F) – wire mesh filter
observe temperature limits of transmitter
electronics
HygroClip IC-1 (100mm) / IC-3 (250mm)
for through-wall installation
max. 200°C (392°F) - wire mesh filter
HygroClip IM-1 (120mm) / IM-3 (270mm)
for through-wall installation in high humidity
applications
max. 200°C (392°F) - wire mesh filter
HygroClip IE-1 (G ½”) / IE-2 (NPT ½”)
for compressed air (max. 50 bar / 725 PSI)
max. 85°C (185°F) – sintered steel filter
to avoid errors, temperature should be the
same on both sides of the mounting wall
HygroClip IC-05
for measurement in tight spaces
max. 100°C (212°F)

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Analog Probes
Depending on the model and options, the HygroFlex transmitters can be used with one or two
analog probes. Both the scale and unit of the analog input signals can be defined with the HW3
software. For example, an analog pressure probe may used to provide the local value of barometric
pressure for the computation of parameters such as the wet bulb temperature, mixing ratio or
enthalpy.
HygroClip ID
for through-wall installation
max. 200°C (392°F) at sensors – wire mesh filter
available with up to 700mm (27.6”) probe length
Probe Extension Cable AC1616/xxx
with built-in signal booster
xxx = 002 to 200
from 2 to 200 m (about 6.5ft to 656ft)
max. temperature 85°C (185°F)
HygroClip ID-EX-xxx (intrinsically safe)
for through-wall installation
xxx = 002 to 100
from 2 to 100 m cable length (about 6.5ft to 328ft)
max. temperature at sensors: 200°C (392°F)
probe length 250 mm - sintered steel filter
HygroClip IW-EX-xxx (intrinsically safe)
for surface mount (area monitoring)
xxx = 002 to 100
from 2 to 100 m cable length (about 6.5ft to 328ft)
max. temperature 40°C (104°F)
probe length 150mm
sintered steel filter
ZB1 Zenner Barrier for ID-EX and IW-EX
AC1617xxx Connecting Cable for ZB1
with built-in signal booster
xxx = 002 to 100
2 to 100m (about 6.5ft to 328ft)

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Use of analog probes is subject to the following restrictions and limitations:
a) ROTRONIC analog humidity-temperature probes with the standard temperature output signal of
– 0.5…2.0 V = -50…200°C: because the HygroFlex cannot read a negative voltage signal,
temperature measurement is generally limited to values above freezing.
b) Third-party analog probes: single channel probes (one signal), output signal within the range of
0 to 2.5 VDC, supply voltage: 15 VDC or less, maximum current consumption: 10 mA.
c) Resolution is limited by the 10-bit A/D converter used for the analog inputs. This converter
provides a theoretical maximum of 1024 counts for an input voltage span of 2.5 VDC. In theory,
this gives a resolution of 2.5 / 1024 = 0.00244 V. In practice, it is not possible to get 100% of the
counts from an A/D converter and the actual resolution should be about 0.0027 V (typical). For
example, if a probe with a temperature signal of 0..1 V = 0…100°C is being used, the signal
resolution will be about 100 x 1 x 0.0027 = 0.27°C
Analog Outputs (HygroFlex 1 and HygroFlex 3)
Model HygroFlex 1 HygroFlex 2 HygroFlex 3
analog outputs - relative humidity
- temperature N/A (digital output only) - relative humidity - temperature
- computed parameter 1)
output signals 2)
configurable with
jumpers
0…1 V
0…5 V
0…10 V
0…20 mA
4…20 mA
N/A 0…1 V
0…5 V
0…10 V
0…20 mA
4…20 mA
D/A output
resolution humidity: 12-bit temperature: 16-bit N/A humidity: 12-bit temperature: 16-bit
comp. parameter: 12-bit
options floating analog current
outputs N/A floating analog current outputs
16-bit D/A resolution for
the computed parameter
analog output, allows 0.1
resolution with a span of
more than 200 units.
1) The computed parameter and its range are set at the factory as specified when ordering. These
settings can be changed at any time with the optional HW3 software or with the optional display and
keypad. To prevent unauthorized or accidental changes, HW3 has provisions to block out access to
the computed parameter function from the keypad.
2) The output signals are set at the factory according to the type and range specified when ordering. A
label located on the transmitter housing shows the type of output signal for each unit.
The analog output signals are linear and are consistent with the requirements of most data/signal
processing instrumentation (panel meter, controller, computer card, etc.).

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RS232 Digital Port
The HygroFlex 1 has an internal RS232 service connector. Both the HygroFlex 2 and 3 have an
external RS232 connector (located on the connector plate). In principle, any communication
software can be used to interrogate and read the HygroFlex with the commands described in
appendix 7 (RS232 communication protocol). Use of the optional HW3 software simplifies this task.
It is important to note the following:
a) HygroFlex 1: use of the RS232 port (internal service connector) is limited to configuring the
instrument (units, range, etc.). Measurement data and calibration functions are not available on
this port.
b) HygroFlex 2 and 3: use the RS232 port to configure the transmitter, calibrate the probe and
connect the transmitter to a network. The computed parameter (dew point or other) is not part
of the digital communication (limited to %RH and temperature – in the unit selected for the
transmitter).
HW3 Software
The HW3 software (optional) allows real time computation of the dew point (or other) by the PC
while providing additional functionality such as:
-RS485 networking (up to 32 units)
-full access to instrument configuration (unit system, etc.)
-calibration of the ROTRONIC HygroClip digital probes with or without HygroFlex
-data logging to a PC disk file
-graphic functions (both on and off-line)
HW3 runs on any PC with Windows 98 or NT. For more details see separate instruction manual
provided with the HW3 software.
RS485 Networking (HygroFlex 2 and HygroFlex 3)
With the optional HW3 software up to 32 HygroFlex 2 or 3 transmitters can be connected together
on a network. Any transmitter can be used either as a slave or a master, without special
configuration. Each unit must be given a unique network address with the HW3 software (0 to 31).
The master is automatically the unit that is connected to the COM port of the PC by means of the
RS232 port. See Electrical Installation for details.
RS232: 3 wires (including ground wire)
RS485: 2 wires
PC
(HW3)
COM Port
Unit 0
Unit 1
Unit 31
RS232
RS485
RS485
RS485
RS232
RS232
RS232 up to 150m (490 ft)
RS485 up to 1000m (3300 ft)

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Unit System
The unit system of the HygroFlex (Metric or English) is factory programmed as specified when the
instrument was ordered. The unit system can be easily be changed by the user with the optional
HW3 software.
Optional Display and Keypad
The LC display shows which probe input is being displayed (small indicator on top of the display)
and up to 2 parameters measured by the probe, with the associated engineering unit. When
relevant, the message line provides additional information.
ss
zz 8.8:8.8 zzzz
zz 8.8:8.8 zzzz
zzzzzzzzzzzzzzzzz
Keypad
Humidity and Temperature
Calculated Value and Temperature
Calculated Value and Humidity
Probe Input Indicator
(1-2) from left to right
Engineering
Units
Message Line
Parameter
MENU :Press this key to activate the function menu. The different
menu items appear on the LCD message line. Press this key again
to exit the menu
UP / DOWN: Press one of these keys to select the probe input
for the display and functions. When the function menu is active,
use these keys to navigate the menu, make a selection or to
change a number on the display.
ENTER: When the menu is active, press
this key to confirm a selection.

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Installation
Mechanical Installation
Installation of the Transmitter Enclosure
The HygroFlex includes 5 parts that can be separated one from the other: wall plate (1), electronics
housing (2), electronics module (3), connector plate (4) and front cover with or without optional
display and keypad (5).
1) Attach the wall plate in the position shown above to an appropriate surface using 4 screws.
2) Slide the electronics housing down on the wall plate to the mechanical stop
To remove the cover, insert a screwdriver in the V-shaped slot on top of cover and press to
unlock prior to pulling the cover away from the electronics housing. If the cover has the optional
display and keypad, it is is connected to the electronics module by a ribbon cable that is
inserted in two zero-insertion-force connectors (see below).
Cover with optional Display and Keypad
Zero-insertion-force connectors are used both inside of the cover and on the electronics module.
With this type of connector, the ribbon cable can be disconnected by gently pulling on it. The cable
is connected simply by inserting it in the connector. To lock the connector and establish positive
contact, press down on the outside connector frame. Each end of the ribbon cable has non-
insulated and an insulated side. The insulated side is indicated by the blue color. When inserting
the cable in the connector, pay attention to the position of the blue side of the flat ribbon cable as
indicated below. If the cable is disconnected and then reconnected while the transmitter is
powered, the display may become blank. In that case, unpower and power again the transmitter.
1
2
3
4
5
Electronics Module
Display
Connector
Blue side of
ribbon cable
UP
Cover (inside)
Connector
Blue side of
ribbon cable
UP
V-shaped
slot

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Probe Installation
Do not remove the dust filter or slotted cap from the probe. Both sensors can easily be damaged
when not protected
-Install the probe at a location where humidity, temperature and pressure conditions are
representative of the environment or process to be measured. Avoid the following: (a) Close
proximity of the probe to a heating element, a cooling coil, a cold or hot wall, direct exposure to
sun rays, etc. (b) Close proximity of the probe to a steam injector, humidifier, direct exposure to
precipitation, etc. (c) Unstable pressure conditions resulting from excessive air turbulence.
-If possible, choose a location that provides good air movement at the probe: air velocity of at
least 1 meter/second (200 ft/ minute) facilitates adaptation of the probe to changing temperature.
-When installing the probe through a wall, immerse as much of the probe as possible in the
environment to be measured.
OK
NG NG
Small Diameter Duct
Short Probe
OK NG
9 to 9.5" immersion
Position the probe so as to prevent the accumulation of condensation water at the level of the
sensor leads. Install the probe so that the probe tip is looking downward. If this is not possible,
install the probe horizontally.
Depending on the probe model, a probe holder (mounting flange with a compression fitting) can
facilitate installation through a wall.
Future maintenance can be made easier by providing next to the probe a calibration access orifice.
During maintenance, this permits the insertion of a reference probe (calibrator).The calibration
access orifice should have the same size as the orifice used to install the probe and can be
equipped with a probe holder.

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Electrical Installation
Terminal Blocks
The terminal blocks of the HygroFlex are of the plug-in type.
If the electronics module has to be removed from the enclosure, simply unplug the terminals from
the electronics module, without undoing the wiring.
Connection Plate
The configuration of the connection plate depends both on the model and on the options that were
ordered for the HygroFlex.
1) power and analog outputs: depending on the options, the connector plate may be equipped with cable grips,
with 1/2” conduit adapters or with connectors.
probe input 2 (optional / depends on model):
-third-party analog probe
-
HygroClip probe with adapter cable
RS232 / RS485 (depends on model)
analog outputs
1)
(depends on model)
power
1)
probe input 1
-HygroClip probe
-analog probe with adapter cable
test (calibrator)
GND
DIO
AIN+
GND
DIO
V++
485 –
485 +
GND
RX
TX
AIN2+
AIN1+
GND
DIO
V++
OUT 1 +
OUT 2 +
OUT 3 +
GND
AC N / DC -
AC Ph / DC +
GND
probe input 1
test
probe input 2 (optional / depends on model)
RS232 / RS485
(optional / depends on model)
analog outputs (depends on model)
Power
Electronics Module
See also
connector diagrams
TB2: 4 3 2 1 TB1: 3 2 1

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The connectors are factory pre-wired to the terminal blocks of the electronics module. Depending
on the transmitter model and options, matching connectors are shipped together with the
transmitter. If the connector plate is equipped with cable grips or conduit adapters for the analog
outputs and power, the wiring connections to the electronics module have to be made at the time of
the installation.
Connector Diagrams
Probe 1 – TUCHEL (7-pin shown from solder side))
Pin # Function Pos. on Terminal Block (PCB)
EGND 3
1Temperature – analog (+) 5
3DIO (digital) 2
5+ VDC 1
6Humidity – analog (+) 4
Test Connector (2-pin shown from solder side)
Pin # Function Pos. on Terminal Block (PCB)
1DIO (digital) 1
2GND 2
Probe 2 (5-pin shown from solder side) – optional (e.g. pressure)
Pin # Function Pos. on Terminal Block (PCB)
2+ VDC 1
3GND 3
4DIO (digital) 2
5Analog (+) 4
RS232 / RS485 (5-pin shown from solder side)
Pin # Function Pos. on Terminal Block (PCB)
1TXD 1
2RXD 2
3GND 3
4RI + 4
5RI - 5
Analog Outputs (4-pin shown from solder side) – optional
Pin # Function Pos. on Terminal Block (PCB)
1Output 1 (+) 1
2Output 2 (+) 2
3Output 3 (+) 3
4GND 4
RS232 connection (PC side)
Pin # Function
2RX
3TX
5GND

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Electrical Diagrams (analog outputs)
Before making the electrical connections, be sure to correctly identify each connector and terminal.
Applying power to any of the input or output terminals can severely damage the transmitter.
12 to 35 VDC or 12 to 24 VAC supply voltage and voltage output signals
TB1 (2) 12…35 VDC (+) or 12…24 VAC neutral TB2 (1) Relative humidity (+)
TB1 (1) 12…35 VDC (-) or 12…24 VAC Ph TB2 (2) Temperature (+)
TB1 (3) Ground TB2 (3) Calculated Parameter (+)
TB2 (4) Common (-)
90…264 VAC with optional power module and current output signals
TB1 (2) 90…264 VAC Neutral TB2 (1) Relative humidity (+)
TB1 (1) Phase TB2 (2) Temperature (+)
TB1 (3) Ground TB2 (3) Calculated Parameter (+)
TB2 (4) Common (-)
RL
1)
RL
1)
R
L
1)
1) minimum load:
1000 ohm
~
~
TB1 TB2
2
1
1
3
1
2
3
4
~
RL
1)
RL
1)
R
L
1)
1) maximum load :
500 ohm
wiring included.
~
~
TB1 TB2
2
1
1
3
2
3
4
~

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Floating Current Outputs (option)
1) maximum load : 500 ohm, wiring included
Power Supply Cable
If the transmitter was supplied with cable grips, please note that the cable grips provide effective
sealing only with cables having the proper outside diameter. Preferably, use a cable with an outside
diameter of 6 to 7 mm (0.236 to 0.275”) and with 18AWG wires. Seal any unused cable grip. We
generally recommend grounding the HygroFlex, especially if the electronics will be subjected to a
low humidity environment (35 %RH or less).
Analog Signals Cable
Generally, we recommend running the analog signal cable separately from the power cable.
If the transmitter was supplied with cable grips, please note that the cable grips provide effective
sealing only with cables having the proper outside diameter. Preferably, use a cable with an outside
diameter of 6 to 7 mm (0.236 to 0.275”) and with 18AWG wires. Depending on the installation, you
may have to use a cable with twisted pairs or a shielded cable to avoid interference. Seal any
unused cable grip.
In order to determine the maximum length of cable that can be used to connect the transmitter to
other devices, the first step is to find out what is the resistance per unit of length of the cable that
you plan on using.
.Current outputs: the maximum permissible cable length, connecting the unit to other devices, is
determined by the total resistance resulting from the addition of the cable resistance and that of
the devices connected in series with the unit. This resistance should not exceed 500 ohms.
.Voltage outputs: the maximum cable length can be determined under consideration of the voltage
drop caused by the current flowing to the devices connected to the unit. The voltage drop in the
cable depends both on cable resistance and on the equivalent resistance of the devices
connected in parallel to the unit. The total resistance connected to each unit output must at least
be equal to 1000 ohm. Cable resistance should not be more than 1/1000 of the load resistance.
RL
1)
RL
1)
RL
1)

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Network Configuration and Wiring (HygroFlex 2 and HygroFlex 3)
The RS232 connection between the HygroFlex and a PC requires 3 wires: RX, TX and GND 1) .
Without a signal booster, the maximum cable length is limited to 150 m (490 ft).
1) GND is internally connected to the power ground of the transmitter
The RS485 wiring can be done with a twisted pair (2-wire, telephone type) and wall mounted RJ45
receptacles. No shielded cable and no terminator should be required.
AC1624
A 2-cable, 5-pin connector was supplied with each unit (see Connector Diagrams). Both the RS232
and RS485 wiring share this connector on the first unit (0). Be sure to observe the polarity for each
connection.
PC
COM
RS232 (3 wires)
maximum 150 m (490 ft) RS485 ( 2 wires) maximum 1,000 m (3,300 ft)
can be left open ended
RJ45
2 wires
2-cable
connector
Unit 0
Unit 1
Unit 2
Unit 31
Prior to networking the transmitters
, these should be individually configured with the HW3
software (see separate instructions on the HW3 CD ROM). Proceed as follows:
1) Connect each transmitter, one at a time, to the COM port of the PC
2) Assign to each transmitter a unique network address (a number between 0
and 31). By default, all transmitters are shipped by the factory with address 0.
3) For easier identification, you may also want to give at that time a descriptive name
(maximum 30 characters) to each transmitter.

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Configuration of the Analog Outputs
On the HygroFlex 1 and HygroFlex 3, the type of output signal can be selected by means of two
jumpers for each output. These jumpers are located on the PCB of electronics module:
Signal OUT1 OUT2 OUT3 1)
0…1 V B2, B3, B31 B12, B13, B31 B22, B23, B31
0…5 V B2, B4, B32 B12, B14, B32 B22, B24, B32
0…10 V B2, B5, B31, B32 B12, B15, B31, B32 B22, B25, B31, B32
0…20mA B1, B3, B33, B34 B11, B13, B33, B34 B21, B23, B33, B34
4…20mA B1, B3, B31, B33, B34 B11, B13, B31, B33, B34 B21, B23, B31, B33, B34
1) HygroFlex 3 only (computed parameter)
The scale (or range) of each analog output can be changed with the HW3 software (see separate
instructions). On the HygroFlex 3, the parameter corresponding to the third output can also be
changed with the HW3 software (see separate instructions).
Functions
The functions can be accessed either with the optional display and keypad or by connecting a
HygroPalm indicator to the Test connector of the HygroFlex (see Remote Mode). Some functions,
including all calibration functions, can also be accessed with the HW3 software.
To access the function menu from the HygroFlex keypad, press the MENU key. The first menu item
appears on the message line of the LC display. Use the UP or the DOWN key to navigate the
menu. When the desired menu item appears on the message line of the LC display, press the
ENTER key to select. Some menu items have sub-items. These can be selected with the UP,
DOWN and ENTER keys. To exit the menu and return to the normal display mode, press the
MENU key. The instrument also returns automatically to the normal display mode when no key is
being pressed for some time (main menu: 10 sec., submenu: 30 sec.).
B31
B32
B33
Res.
RS232 / RS485
HygroFlex 1: to configure the temperature range
and unit, use this 3-pin service connector and
connect to a PC with cable # AC1623.
HygroFlex 3: the transmitter can be configured
by connecting the RS232 / RS485 output to a
PC.
For both transmitters, configuration requires the
HW3 software installed on the PC.
B34

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CALCULATE (HygroFlex 2 and HygroFlex 3)
Definition
This function is used to select the humidity parameter that is calculated and displayed by the
instrument 1) . Any selection made here has no effect on analog output #3 (computed parameter) of
the HygroFlex 3. Use the HW3 software to change the computed parameter sent this output.
1) does not apply to third-party analog probes.
The calculated parameter is selected individually for each probe connected to the instrument 1).
Prior to entering this function, select on the display the probe input to programmed.
The unit system (Metric or English) is factory programmed according to what was specified when
the instrument was ordered. The unit system can be selected with the optional HW3 software (see
separate instructions).
Selections
Parameter MEHygroFlex 1 HygroFlex 2 HygroFlex 3
Dew Point / Frost Point 1) °C°FN/A x x
Wet Bulb Temperature °C°FN/A x x
Enthalpy J/g BTU/lb N/A x x
Vapor Concentration g/m3gr/cuft N/A x x
Specific Humidity g/kg gr/lb N/A x x
Mixing Ratio g/kg gr/lb N/A x x
Vapor Concentration
at Saturation g/m3gr/cuft N/A x x
Partial Pressure
of Water Vapor hPa PSI In Hg N/A x x
Saturation Pressure
of Water Vapor hPa PSI In Hg N/A x x
Pressure Constant 2)
(Barometric Pressure) hPa PSI In Hg N/A x x
1) The standard factory setting is frost point for values below freezing. This setting can be changed
to dew point with the optional HW3 software
2) This selection shows the fixed value that is used for computing the parameters that require
barometric pressure as an input. The fixed pressure value can be changed with the optional HW3
software. Both the HygroFlex 2 and HygroFlex 3 can also be programmed to accept the input from
a pressure probe (variable pressure value).

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DISPLAY (HygroFlex 2 and HygroFlex 3)
Definition
This function is used to select which parameters are displayed by the instrument. The display mode
is specified globally for all humidity probes connected to the instrument.
HygroFlex 3: the display selection has no effect on the analog outputs.
Selections
-Measurement
Relative humidity and temperature or the parameter measured by any third party probe
connected to the instrument.
-Calculated + Temperature
Calculated parameter (as selected under CALCULATE) and temperature. This selection is not
available with third-party probes.
-Calculated + Humidity
Calculated parameter (as selected under CALCULATE) and relative humidity. This selection is
not available with third-party probes.
ADJUST M.PT (2- to 4-point adjustment against a reference environment)
Definition
The Adjust M.PT function permits to calibrate and adjust a ROTRONIC HygroClip digital probe
against a known reference environment. This function is designed to permit calibration at 2
temperature values and at up to 4 relative humidity values.
Selections
The Adjust M.PT function offers the following selections:
RHS:Humidity calibration using the ROTRONIC Humidity Standards 1)
Humidity:Humidity calibration using any suitable reference environment
Temperature:Temperature calibration using any suitable reference environment
1) For humidity calibration, ROTRONIC offers convenient, certified humidity standards to generate known
humidity values (for more details, see Appendix 3 - Humidity Calibration).
Procedure
When two probes are connected to the transmitter, be sure to select on the display the HygroClip
probe to be calibrated prior to entering the function.

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Regarding the Adjust M.PT function, it is important to observe the following rules:
a) Always calibrate temperature first (if temperature needs to be calibrated)
b) When calibrating temperature (2 points), always calibrate at the low value first. The instrument is
programmed to use the low temperature value to compute the offset and the high temperature
value to compute the gain.
T-low < 70 °C (158°F) : used to compute the calibration offset
T-high = 70 °C (158 °F) : used to compute the calibration gain
For best accuracy, we recommend using a T-low value close to 20°C (68°F). Preferably, the
difference between T-high and T-low should be at least 50 °C (90 °F)
c) When calibrating relative humidity (2, 3 or 4 points) with the ROTRONIC humidity standards,
always follow the sequence 35 %RH, 80 %RH, 10 %RH or 5 %RH, 0 %RH. When using a
reference other than the ROTRONIC humidity standards, use reference conditions that are
within the following brackets and observe the sequence:
>25 %RH…=55 %RH 1) : used to compute the calibration offset
>55 %RH 1) : used to compute the calibration gain
>1 %RH…=25 %RH : sensor linearity adjustment
= 1 %RH : sensor linearity adjustment
The HygroFlex is programmed to automatically recognize these brackets.
1) For best accuracy, we recommend using values close to 35 %RH and 80 %RH
When the probe is at equilibrium with the reference environment, activate the Adjust M.PT function
and make the appropriate selections:
a) RHS: press the ENTER key to select this item. The LC display shows the value of the standard
(for example 35.0%RH) on the top line and “Humidity RHS” on the message line. Verify that the
value agrees with the standard being used. If necessary, change the value of the standard with
the UP or the DOWN key. Press the ENTER key when done.
Note: the software automatically compensates for the effect of temperature on the humidity
standard. No additional correction is required.
b) Humidity or Temperature: press the ENTER key to select. The LC display shows the value
read by the probe at the time the ENTER key was pressed. The word “humidity” or
“Temperature” is shown on the message line. Use the UP or the DOWN key to change the
humidity or temperature value to match the value of the reference environment. For a faster
change, keep the key pressed down. Press the ENTER key when done.
After pressing the ENTER key, the message “sure?” should appear on the LC display. Press
ENTER to confirm. Next, the LC display will confirm that the probe adjustment has been
successfully completed. At that time, press ENTER to exit or MENU to return to the function Adjust
M.PT and do another calibration point.
Carry on in the same manner for each calibration point, following the sequence described above.
Note: you can exit the function at any time (without calibrating the probe) by pressing the MENU
key.