Rotronic HygroLog HL-NT2 User manual

IN-E-HL-NT-V2_12
Rotronic AG
Bassersdorf, Switzerland
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Unit
HygroLog HL-NT data logger:
instruction manual
Instruction Manual
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© 2009-2012; Rotronic AG IN-E-HL-NT-V2_12
HygroLog HL-NT Data Logger
Instruction Manual

IN-E-HL-NT-V2_12
Rotronic AG
Bassersdorf, Switzerland
Document code
Unit
HygroLog HL-NT data logger:
instruction manual
Instruction Manual
Document Type
Page
2of 48
Document title
© 2009-2012; Rotronic AG IN-E-HL-NT-V2_12
Table of contents:
1. Overview.................................................................................................................................. 3
1.1 General................................................................................................................................ 3
1.2 Compatibility with previous models of probes and docking stations ................................... 4
2. General description of the HygroLog HL-NT....................................................................... 5
2.1 Models ................................................................................................................................. 5
2.2 Required accessories.......................................................................................................... 5
2.3 HygroLog HL-NT inputs....................................................................................................... 5
2.4 Power supply ....................................................................................................................... 8
2.5 Memory card........................................................................................................................ 9
2.6 LED Indicators ................................................................................................................... 10
2.7 Beeper ............................................................................................................................... 10
2.8 HygroLog HL-NT functions................................................................................................ 10
2.9 HygroClip 2 probe functions .............................................................................................. 13
2.10 Event tracking.................................................................................................................... 14
2.11 Operating limits (electronics only) ..................................................................................... 16
3. Docking stations for the HygroLog HL-NT ........................................................................ 17
3.1 Models ............................................................................................................................... 17
3.2 Installation.......................................................................................................................... 20
3.3 Docking station inputs........................................................................................................ 25
3.4 Relay contacts................................................................................................................... 26
4. Pin-out diagrams.................................................................................................................. 26
5. HW4 software........................................................................................................................ 28
5.1 Computer/Operating System Requirements ..................................................................... 28
5.2 Operating System Compatibility ........................................................................................ 29
5.3 Settings and functions accessible only with HW4 ............................................................. 29
6. ERES regulatory compliance.............................................................................................. 30
7. Getting started...................................................................................................................... 31
8. Stand-alone operation ......................................................................................................... 31
8.1 Operating modes............................................................................................................... 31
8.2 Display and keypad ........................................................................................................... 31
8.3 Display modes................................................................................................................... 33
8.4 Settings and functions accessible from the Keypad.......................................................... 33
8.5 Internal function menu (models with display and keypad)................................................. 34
9. Operation on a network ....................................................................................................... 37
9.1 Baud rate and communications protocol compatibility requirements................................ 37
9.2 Ethernet local area network............................................................................................... 37
9.3 RS-485 multi-drop network................................................................................................ 38
9.4 General wiring guidelines .................................................................................................. 39
9.5 Guidelines for RS-485 wiring............................................................................................. 40
10. HygroClip probe adjustment procedures ..................................................................... 41
10.1 Single Point adjustment..................................................................................................... 41
10.2 Multi-Point adjustment....................................................................................................... 42
11. Warnings and useful tips................................................................................................ 42
12. Communications protocol.............................................................................................. 43
13. Firmware updates............................................................................................................ 43
14. Specifications .................................................................................................................. 44
15. Accessories...................................................................................................................... 47
16. Supporting documents ................................................................................................... 47
17. Document releases.......................................................................................................... 48

IN-E-HL-NT-V2_12
Rotronic AG
Bassersdorf, Switzerland
Document code
Unit
HygroLog HL-NT data logger:
instruction manual
Instruction Manual
Document Type
Page
3of 48
Document title
© 2009-2012; Rotronic AG IN-E-HL-NT-V2_12
Applicability:
This manual is valid for instruments with firmware version 2.0x (see MENU - Instrument or check
using the ROTRONIC HW4 software, Device Manager). Examples: 2.0a, 2.0b. Changes in the
last character of the version number reflect minor changes in the internal software of the
instrument that do not affect the manner in which the instrument should be operated.
1. Overview
1.1 General
HygroLog HL-NT is a series of networkable data loggers primarily designed for use with the
HygroClip 2 digital humidity-temperature probes.
Depending on the model and options, the HygroLog HL-NT main features are as follows:
oInternal probe input: allows installing a HC2-S humidity-temperature probe internally to
prevent unauthorized removal. This input can also be connected to an external probe by
means of an extension cable.
oInputs for up to 6 additional external probes, including analog probes and 4-wire passive
RTD probes.
oMonitoring of up to two external contacts (relay output, door, etc.).
oLarge recording capacity with removable flash memory card. Up to 750,000 values can
be recorded with the standard 16 MB card. Cards with a capacity of up to 1 GB are
available.
oDisplay with backlight and keypad. This allows the HygroLog HL-NT to operate as a
stand-alone unit after initial configuration with the HW4 software.
oCompliance with FDA 21 CFR Part II and GAMP regulations regarding electronic records
and electronic signatures (ERES).
oCompatible with Ethernet networks (TCP / IP protocol –LAN or WLAN).
oDedicated RS-485 network of up to 64 HygroLog HL-NT per communication port
oSimultaneous data recording and data display either locally or on a PC.
Internal power for both the HygroLog HL-NT and probes is provided by a 9V battery (factory
standard) or by a 9V rechargeable battery (user supplied).
The HygroLog HL-NT requires a docking station to (a) to power the HygroLog HL-NT with an
external AC adapter, (b) to configure the HygroLog HL-NT and communicate with a PC, (c) to
connect the HygroLog HL-NT to a network and (d) to mount the HygroLog HL-NT to a wall or to
place the HygroLog HL-NT on the optional desk-top stand.
The most basic model of docking station simply provides a means of mounting the HygroLog HL-
NT to a wall and of powering the HygroLog HL-NT with an external AC adapter. All other models
offer the same functionality as the basic model and also provide a communication port (RS232,
USB or RJ45 / Ethernet) as well as additional inputs for probes and external contacts. Docking
stations with an RS232 or USB port are used to connect the HygroLog HL-NT directly to a PC.
Docking stations with an RJ45 connector are used to connect the HygroLog HL-NT to an Ethernet
LAN. In both cases, the docking station features an RS485 port that can be used to connect up to
64 HygroLog HL-NT in a multi-dropped arrangement (dedicated RS-485 network). This is useful
when the PC does not have an Ethernet network interface card or when the number of available

IN-E-HL-NT-V2_12
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HygroLog HL-NT data logger:
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Ethernet ports is limited. Direct connection to an Ethernet LAN allows, in principle, an unlimited
number of HygroLog HL-NT to be put on a network monitored by the HW4 software. HW4 allows
any combination of RS-232, USB, Ethernet and RS-485 connections.
When equipped with a docking station, the HygroLog HL-NT can be used together with the
ROTRONIC HW4 software for Windows based PCs (version 2.3.0 or higher). In addition to
providing for the networking of large quantities of data loggers and other instruments, the main
functions of HW4 include:
oConfiguration of the HygroLog HL-NT and docking station
oProgramming of the HygroLog HL-NT logging function
oManual or automatic downloading of the data recorded by the HygroLog HL-NT
oOn-line data monitoring and direct data recording by the PC
oAutomatic generation of graphs and data tables
oMonitoring of the networked instruments and data for alarm conditions
oAlarm reporting
oMaintenance of audit trails
oCalibration and adjustment of the HygroClip 2 probes
oGeneration of protocols, electronic signatures, etc.
A high level of protection against network failures can be achieved by logging data directly on the
PC while also recording the data locally on the HygroLog HL-NT with automatic download to the
PC at regular interval of times.
Note: Instructions for using the HW4 software are not included in this manual. These instructions
are shipped separately on the software CD ROM.
1.2 Compatibility with previous models of probes and docking
stations
oThe HygroLog HL-NT is designed for use with the HygroClip 2 probes (UART interface)
and is not compatible with the previous generation of HygroClip probes (DIO interface).
oDocking stations designed for the previous generation of HygroClip probes (such as DS-
U1, DS-U4, etc.) are not compatible with the HygroLog HL-NT.
oRS-485 drop-down networks: the HygroLog HL-NT is compatible with previous versions
of the HygroLog NT and with other legacy products. The HygroLog HL-NT cannot be
used in the same RS-485 drop-down as a HF4 or HF5 transmitters or any product that
rely on the RO-ASCII communications protocol.
oUnlike previous versions, The HygroLog HL-NT does not have a remote mode

IN-E-HL-NT-V2_12
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2. General description of the HygroLog HL-NT
2.1 Models
Basic models without display and keypad
oHygroLog HL-NT2: logger for plug-in HygroClip 2 probe (probe is not included and must
be ordered separately). Probe model HC2-S can be mounted either internally or in the
extended position. Other probe models are external and require an extension cable.
oHygroLog HL-NT3: same as HL-NT2 with 2 additional connectors suitable for a
HygroClip 2 digital probe.
Models with display and keypad
oHygroLog HL-NT2-D: same probe as HygroLog HL-NT2
oHygroLog HL-NT3-D: same probe / probe inputs as HygroLog HL-NT3
Models with internal HC2-S probe pre-installed
oModels HL-NT2-P, HL-NT2-DP, HL-NT3-P and HL-NT3-DP are supplied with an internal
HC2-S probe pre-installed.
2.2 Required accessories
●Models without display/keypad:
The following accessories are required in order to be able to use the logger:
- Any model of docking station (except model DS-NT1)
- Connecting cable docking station to PC
- PC with the ROTRONIC HW4 software installed (version 2.3.0 or higher)
●Models with display/keypad:
In principle, these models can be used without any accessory. However, accessing all of the
product functions and changing some important settings such as the date and time requires the
same accessories as for the models without display.
2.3 HygroLog HL-NT inputs
2.3.1 Probe input 1
HygroLog HL-NT2-P, HL-NT2-DP, HL-NT3-P and HL-NT3-DP: these models are supplied with
an internal HC2-S plug-in probe. This probe can be either retracted or extended. The probe can
also be separated from the logger with an extension cable, and in this case the HC2-S probe may
be replaced with another model of HygroClip 2 probe so as to meet specific application

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requirements (see document E-M-HC2 Probes-V1). Open the housing of the HygroLog to
change the position of the probe or to install a probe extension cable.
To extend the probe, lift the HygroClip S probe from its position and remove the slotted cap from
the HygroLog. To extend the probe, place on the probe the ring supplied with the HygroLog.
Insert the ring into the slot in the instrument housing where the slotted cap was. Relocate the
probe connector up by one or two ribs. Close the instrument housing. Proceed in a similar
manner to install a probe extension cable.
HygroClip S
extended position
Extension cable used to
separate the probe from
the HygroLog.
Ring
(replaces the slotted cap)
To open the housing of the
HygroLog, remove the five
screws, as indicated by the
arrows.
The far right drawing shows
the HygroClip S probe in the
retracted position. The base
of the probe is plugged into
a connector that is
separated from the main
board by a length of wire.
Probe
connector
The shorter screw
goes here

IN-E-HL-NT-V2_12
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Notes:
oFor maximum protection against vandalism, use the HC2-S probe in the retracted
position. For a faster response, use the probe in the extended position.
oFor additional information on the HygroClip 2 probes see document
E-M-HC2 Probes-V1.
2.3.2 Probe inputs 2 and 3 (HygroLog HL-NT3)
The HygroLog HL-NT3 can be used with up to 2 additional HygroClip 2 probes. For further
information on the HygroClip 2 probes, see document E-M-HC2 Probes-V1.
2.3.3 Connector identification
Input 1 (HygroClip 2 probe)
Input 2 (HygroClip 2 probe)
Input 3 (HygroClip 2 probe)
Input 1 (HygroClip 2 probe)
HL-NT2
HL-NT3

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2.4 Power supply
The HygroLog HL-NT ships with a regular 9V battery which must be inserted first (see battery
replacement).
To conserve battery power, models with the LC display and keypad are shipped with the Display
Sleep function enabled (see Software Functions). When the keypad has not been used for some
time, this function automatically turns off the display off. The display can be temporarily activated
by pressing on any key of the keypad.
When connected to a docking station, the HygroLog HL-NT can be powered with an external AC
adapter.
Note: most models of docking station require the use of an external AC adapter due to the current
consumption of the docking station internal electronics.
After reconfiguring the HygroLog HL-NT with the ROTRONIC HW4.software, a rechargeable
battery (accumulator) can be used instead of a regular battery. Recharging the battery require a
docking station and an external AC adapter.
WARNING: Trying to recharge a regular battery is potentially dangerous. Whenever a
regular battery is being used, the logger should be configured with the internal battery
charge function disabled.
2.4.1 Battery lifetime
The battery lifetime depends on the manner in which the HygroLog HL-NT is being used. The
HygroLog HL-NT has a battery lifetime of one year when just one HygroClip probe is being used
(standard 500 mAh alkaline battery), when no docking station with internal electronics is
connected to the HygroLog HL-NT and when the logger is configured / programmed as follows:
●Display Sleep function enabled (models with display)
●No docking station with internal electronics
●LED and beeper functions disabled
●Log interval set to 15 minutes
Additional examples of battery lifetime (LED turned off, Logging active): in the following table,
LCD means that the LC display is permanently on (Display Sleep function disabled). No docking
station with internal electronics is connected to the HygroLog HL-NT.
Lifetime in days
Rechargeable
Battery
120mAh
Rechargeable
Battery
150mAh
Regular
Battery
500mAh
Regular
Battery
1000mAh
1 Probe / 5s Interval
2.7
3.4
11
22
1 Probe / 5s Interval / LCD
2.1
2.6
8.9
17
1 Probe / 1min Interval
14
17
59
118
1 Probe / 1min Interval / LCD
5.8
7.3
24
48
1 Probe / 15min Interval
89
111
372
744
1 Probe / 15min Interval / LCD
8.9
11
37
74

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Note: the consumption of the display is negligible when the Display Sleep function is enabled.
With the display always on, power consumption is at its highest when the display refresh rate is
set with HW4 to the minimum of 5 sec.
Because of the requirement to keep track of the date and time, the HygroLog HL-NT does not
have a power on/off switch. Every minute, both the date and time are recorded to the internal
EEPROM. Seconds are not recorded. In the event of a relatively brief interruption of power (such
as when replacing the battery), time may fall behind in increments of one minute. Removing the
battery for an extended period of time will cause the logger to completely lose track of the date
and time.
2.4.2 Battery replacement
2.5 Memory card
The HygroLog HL-NT has a non-volatile 64 kb EEPROM internal memory that is used to save the
logger configuration data, the logger events and to temporarily hold measurement data.
The main memory is a plug-in flash memory card. As a standard, the HygroLog HL-NT ships with
a 16 MB card. This card allows the recording of up to 400,000 values in text file format
(unprotected) or up to 750,000 values in binary file format (protected). Memory cards with a
capacity of up to 1 GB can be purchased from third parties. Regardless of its size, the flash
memory card holds a maximum of 512 files and directories, including one logger-configuration
and one logger-event file.
The measurement data can be saved either to a file with extension XLS or to a file with extension
LOG. Files with XLS extension can be read with Notepad or imported into Microsoft Excel. Files
with extension LOG are encoded in binary format so as to prevent data manipulation and can
only be read with the ROTRONIC HW4 software. Both types of files can co-exist on the memory
card. The memory card can be removed from the logger and transferred to a card reader, a PDA,
etc. The flash memory card can also be read without being removed from the logger.
cover
To access the battery,
remove the screw shown
to the right and open the
rubber cover.
The battery is located at
the bottom of the
instrument.
Probe
input 5
battery

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2.6 LED Indicators
The HygroLog HL-NT is equipped with a green and red LED. The logger can be configured with
HW4 to have the green side of the LED flash when logging is active. The red side of the LED can
be made to flash when there is an alarm condition (see note below) and / or when the logger
requires attention (low battery, flash memory card full, etc.)
In the transient alarm mode, the red LED flashes for only as long as the data from a probe
corresponds to an alarm condition. In the durable alarm mode, the red LED stays on even after
the alarm condition has disappeared. When the LED is set to provide a durable alarm, it can be
reset from the keypad or with HW4.
2.7 Beeper
The HygroLog HL-NT is equipped with an internal beeper and can be configured with HW4 to
make a clicking sound when any key is being pressed. The beeper can also be configured to emit
a 5-second non-repeating sound when there is an alarm condition and / or when the logger
requires attention.
2.8 HygroLog HL-NT functions
2.8.1 Calculated parameter
Using the HW4 software, the HygroLog HL-NT can be set to compute for each HygroClip probe
one of the following psychrometric parameters.
oDew point (Dp)
oFrost point (Fp)
oWet bulb temperature (Tw)
oEnthalpy (H)
oVapor concentration (Dv)
oSpecific humidity (Q)
oMixing ratio by weight (R)
oVapor concentration at saturation (Dvs)
oVapor partial pressure (E)
oVapor saturation pressure (Ew)
cover
memory
card
Memory Card:
To access the memory
card, remove the screw
shown to the right and pull
out the rubber cover.
The plug-in flash memory
card is located on top of
the main board.
screw

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Each individual probe input can be associated with a different parameter.
Note: depending on whether dew point or frost point was selected, both the HygroLog HL-NT and
HW4 will display either the symbol Dp or the symbol Fp for values below freezing. The symbol Fp
indicates that the value is a frost point as opposed to being a dew point. Regardless of the dew
point / frost point selection, the symbol Dp is always displayed for values above freezing.
Some of the above parameters require barometric pressure as an input. When an analog
pressure probe is connected to one of the HygroLog HL-NT inputs, the logger can be set to use
the measurement from this probe. When no pressure probe is being used, a fixed pressure value
can be used. This value can be specified as part of the HygroLog HL-NT settings.
2.8.2 Data logging
Data logging requires that a flash memory card be inserted inside the logger. Using the HW4
software, log files can be set to one of the following formats:
●HW4 binary format [LOG]: files in this format are encoded and can be opened only with the
ROTRONIC HW4 software. HW4 does not allow any manipulation / alteration of the data and
requires a password to log in. Should the file be somehow modified, HW4 will give a warning
that the file is not an original.
●Text file format [XLS]: in principle, files in this format can be opened with any text editor and / or
imported into Microsoft Excel.
The log file format is a global setting of the flash memory card (changing this setting requires the
HW4 software). At any given time, the card records data from all inputs in either one format or the
other. Files of different formats can co-exist in the flash memory card. Binary files (protected) use
substantially less memory space than text files (unprotected).
The logging function is independently activated for each individual input. The HygroLog HL-NT
creates a separate file for each input that is to be recorded. Multiple inputs cannot be recorded to
the same file. The HygroLog HL-NT automatically generates each file name. A file name consists
of 8 digits followed by the extension LOG or XLS. The first 4 digits are the same as the last 4
digits of the logger serial number, the 5th digit is the same as the input number and the last 3
digits are a number between 000 and 999 used to differentiate log files created for the same
input. The last number that was created is retained in the non-volatile EEPROM and is updated
whenever a new file is created for the input. When the number reaches 999, the next update will
reset it to 000.
All files are located in the root directory of the flash memory card, including the logger event file
and the logger configuration file. Regardless of the memory card capacity, the root directory is
limited to a maximum of 250 files. This means that the memory card can hold a maximum of 248
log files, and that a card with this amount of files is considered to be full, even if all the memory
has not been used.
Using HW4, the following log settings can be defined individually for each input:
●Start date and time
●Stop date and time
●Log interval (minimum 5 seconds)

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●Measured values and computed parameter, or any parameter combination
●User custom text (used for the log file header)
●User name, HW4-ID, HW4 Serial Number
●Automatic creation of a new file after 200,000 data points or at the end of each day, week or
month
Note: unlimited logging (loop mode logging) is not possible. Logging stops automatically when the
flash memory card is full. Prior to logging, the user may use HW4 to check the amount of free
memory, and verify that there is enough room available.
If the flash memory card is removed when logging is active, the HygroLog HL-NT will stop logging
until a new card is inserted. Unless the stop date and time have been reached, logging will start
again under the next available file name when a new card is inserted.
Warning: removing the memory card while logging is active may result in a corrupted log file and
in loss of data.
Logging can be started immediately for any individual input from the keypad of the HygroLog HL-
NT. A deferred start can only be programmed with the HW4 software. The green LED of the
HygroLog HL-NT can be set to flash when the instrument is recording data. To conserve battery
power, you may want to do this only when an external power source is being used.
Logging can be immediately stopped for any individual input directly from the keypad. With HW4,
logging can be stopped either immediately or at a future date and time for any individual input or
for all inputs.
When logging is ended, the HygroLog HL-NT returns to the measuring mode.
2.8.3 Trend indicators
See also: Main operating modes and measurement interval
When the trend indicator function is enabled, a symbol appears on the left side of the LC display,
on the line corresponding to each measured or calculated value. An up arrow denotes a rising
value and a down arrow denotes a decreasing value. Both arrows denote a stable value.
The trend of a parameter is evaluated by comparing successive averages made of 6 values each.
With the shortest possible measurement interval of 5 seconds, each average covers a time period
of 30 seconds and the first indication of a trend is available after one minute. Subsequently, the
trend is evaluated and updated every 30 seconds. With a longer measurement interval, each
average is computed over a longer period of time (always using 6 values) and the trend is also
updated over longer intervals of time.
For any measured or calculated parameter, the trend indicator shows a stable condition when the
absolute value of the difference between two successive averages is < 0.02.
2.8.4 Alarm function
Using the HW4 software, both a high and a low alarm value can be associated with the humidity,
temperature and calculated parameter of each probe input, A hysteresis value can also be
entered for each parameter. This value is used for both the low and the high alarm conditions.

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The HygroLog HL-NT has a red LED which can be set with HW4 to flash whenever the value of
any parameter corresponds to an alarm condition. The LED can be set to flash only as long as
the alarm condition exits or it can be set to provide a durable alarm and, in this case, it will to
keep flashing until the alarm is reset.
The HygroLog HL-NT can also be set with HW4 to beep for 5 seconds when there is an alarm
condition. The HygroLog HL-NT will beep only once, when the condition occurs.
Log files do not record the existence of an alarm condition. However, when the contents of a log
file are viewed as a data table with the HW4 software, values that correspond to an alarm
condition are printed over a red background, based on the alarm settings that HW4 downloaded
from the logger.
2.8.5 Display-Sleep function
This function can be enabled and configured only with the HW4 software.
Using the Display Sleep function can substantially extend the lifetime of the battery. When the
Display Sleep function is active, the LC display of the HygroLog HL-NT stays blank. The Display
Sleep function is effective both in the measure and in the record mode.
The display of the HygroLog HL-NT can be set to be always on. It can also be set to automatically
go blank after 30 seconds, 1, 5, 10 or 20 minutes when no key is being pressed or when there is
no communication with a PC. If the HygroClip NT was in the function menu at the time the display
goes blank, it automatically exits the menu.
The HygroLog suspends the Display Sleep function whenever a key is pressed. The function is
also suspended when external power is available or when the logger receives a communication
request (for example from a PC 1). When the display comes up again, it shows by default the
measurements from the probe that was selected last.
1When the HygroLog HL-NT is connected by means of a docking station to a PC and HW4
is running, you should use an external AC adapter to power both the HygroLog HL-NT and
docking station. HW4 can be set to use a polling interval as short as 5 seconds to interrogate all
instruments connected to the PC and this could cause the battery life time to be sharply reduced.
2.9 HygroClip 2 probe functions
2.9.1 Simulator function (validation of the signal transmission):
If so desired, transmission of the HC2 probe output signals can be validated by using the probe
simulator function. The HW4 software is required to enable and configure this function. When the
function is enabled the probe generates digital and analog signals corresponding to values
specified by the user.
2.9.2 Sensor failure detection and fail safe mode:
The HygroClip 2 probe automatically detects a sensor failure such as a shorted or open sensor.
This information is passed to both the HygroLog HL-NT and HW4 software. The optional display
of the HygroLog HL-NT will show an alarm message. The HygroClip 2 probe can also be
configured with the HW4 software to generate a "safe or readily identifiable" fixed value for
humidity and temperature in the event of a shorted or open sensor.

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Note: the sensor diagnostics and drift compensation function of the HygroClip 2 probe is not
available with the HygroLog HL-NT due to the fact that the probe is powered only briefly during
each log or measurement interval.
2.10 Event tracking
The HygroLog HL-NT maintains an internal event file with the extension EVT. This function is
always enabled.
Part of the procedure to ensure conformity to the FDA requirements is to use the HW4 software
to disable the MENU key on the HygroLog HL-NT keypad. The MENU key is the only key that can
be used to make changes to the HygroLog HL-NT. When this procedure is implemented, the
events recorded by the HygroLog HL-NT are the result of an interaction with the HW4 software.
When the MENU key is not disabled, a limited number of events are recorded in the logger event
file. In this case no entries are made in the logger event file header. The two tables below provide
a list of the events tracked by the HygroLog HL-NT.
The logger event file is split between the internal memory of the logger (up to 170 events) and the
flash memory card (practically unlimited number of events). HW4 offers the possibility of
downloading, opening and printing the entire file contents. All past logger events are available to
HW4 as long as the flash memory card is not removed from the logger. The serial number of the
logger is used as the file name.
Example: 1111111111.EVT
The logger event file consists of a file header and a file body. The file header provides the
following information:
oMost recent programming of the log function: programming date and time, user and HW4
product ID
oMost recent device configuration: date and time, user and HW4 product ID
oMost recent adjustment to the PC date and time: date and time, user and HW4 product ID
An individual record with date and time is entered in the event file body for each individual event
listed in the two tables below:
Interaction with the HW4 software:
Event
Description
Power up
The battery was inserted or the instrument powered down and up after
an internal problem
Watchdog overflow
Internal instrument error (normally should not occur)
Writing device
configuration
New or existing configuration written to logger
Memory card removed
While recording data, the logger could not find the memory card. The
data was written to the EEPROM and are not yet lost
Memory card full
No free memory space on the memory card

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Event
Description
New memory card
inserted
The memory card was replaced while data was being logged. The data
will be split between two different memory cards. Possibly, some data
has been lost.
Humidity adjusted
Humidity adjustment of the probe connected to input #
Temperature adjusted
Temperature adjustment of the probe connected to input #
Logging started
Start recording data from input #
Logging stopped
manually
Data recording of input # ended before the programmed stop time
Logging ended
automatically
Data recording of input # ended at the programmed stop time
Out-of-limits value
detected
An out-of-limits value was newly detected on input #
Battery almost empty
Battery voltage dropped below 6.5V
Battery empty
The battery is empty and the logger has powered itself off (keeping
power up could result in erroneous data or loss of data)
Beginning accumulator
charge
Starting to charge the rechargeable battery
Accumulator charge
ended
Rechargeable battery full
MFG command
Reserved for the factory
Lost data, memory card
not ready
While recording data, the logger could not find the memory card. The
data could not be written to the EEPROM, and was lost
HygroClip probe
connected 1
A HygroClip probe was connected to input #
HygroClip probe
disconnected 1
A HygroClip probe was removed from input # or the input can no
longer communicate with the probe
External power
connected
The A/C adapter was connected and is being powered
External power
removed or faulty
The A/C adapter was disconnected, or failed, or is not being powered
Device time changed /
adjusted
Device date and time prior and after adjustment (up to firmware v1.1d
only)
Prior device time
Device date and time prior to change (firmware v1.2a and up)
New device time
Device date and time after change (firmware v1.2a and up)
RS-485 address
changed
The RS-485 address was changed
EEPROM erased
Reserved for the factory
Docking station
disconnected 2
The docking station was disconnected or there is no longer any
communication with it

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Event
Description
Docking station
connected 2
A docking station was connected and communication was established
Logger language file
downloaded
A different internal language file was loaded or the same file was
loaded again
Log function
programmed
The log function has been programmed for input #
Event file deleted
Reserved for the factory
1connection / removal of analog probes is not recorded
2only when the docking station has internal electronics
Events triggered from the keypad:
Event
Description
Humidity adjusted
Humidity adjustment of the probe connected to input #
Temperature adjusted
Temperature adjustment of the probe connected to input #
Logging started
Start recording data from input #
Logging stopped
manually
Data recording of input # ended before the programmed stop time
Prior device time
Device date and time prior to change (firmware v1.2a and up)
New device time
Device date and time after change (firmware v1.2a and up)
Log function
programmed
The log function has been programmed for input #
2.11 Operating limits (electronics only)
Models without display:
●-10…50°C with the factory supplied alkaline battery
●-30…70°C with a lithium battery or an external AC adapter
Models with display:
●-10…50°C with the factory supplied alkaline battery
●-10…60°C with a lithium battery or an external AC adapter
The HygroClip probes have generally wider operating limits (see individual probe specifications).

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3. Docking stations for the HygroLog HL-NT
The HygroLog HL-NT requires a docking station with the appropriate interface to be able to
communicate with a PC with the ROTRONIC HW4 software installed. The connector located on
the back of the HygroLog HL-NT is meant to be used with one of the available docking stations
(UART interface). When installed on a PC, the ROTRONIC HW4 software is used to configure
the HygroLog HL-NT, to program its logging function, to download the recorded data and to
adjust the probes connected to the logger against a reference environment.
A docking station is required for any of the following:
oMount the HygroLog HL-NT to a wall
oPlace the HygroLog on the optional desk-top stand
oUse an external AC adapter to power the HygroLog HL-NT
oConnect the HygroLog HL-NT to a PC: RS232 or USB port, Ethernet (TCP/IP) LAN
or WLAN
oConnect up to 64 HygroLog HL-NT or other devices together in a multi-dropped network
(RS-485)
Depending on the model, using a docking station also adds functionality to the HygroLog HL-NT:
oUp to 4 additional probes, including analog probes and direct 4-wire RTDs
oLogical inputs (external contacts)
oRelay outputs
Note: docking stations with internal electronics and PC interface should be generally used with an
external AC adapter.
3.1 Models
All models of docking station have the same physical dimensions and can be used either as a
mechanical adapter to place the HygroLog HL-NT on the optional desk-top stand or as a bracket
to mount the HygroLog HL-NT to a wall. Docking stations are available in the following
configurations:
3.1.1 Basic docking stations (no digital interface)
oHL-DS-NT0: basic docking station without internal electronics. This model simply
provides a means of mounting the HygroLog HL-NT to a wall
oHL-DS-NT1: basic docking station without internal electronics (similar to model HL-DS-
NT0). This model simply provides a receptacle for an AC adapter used to power the
HygroLog HL-NT
3.1.2 Docking stations with RS-232 serial interface
oHL-DS-NT2: receptacle for AC adapter, one serial port (RS232) and one RS485 port
(multi-drop).

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oHL-DS-U1: receptacle for AC adapter, one serial (RS232) port, one RS485 port (multi-
drop), four probe inputs (HygroClip 2 or analog probe with voltage output signal), one
connector for up to two logical input signals.
3.1.3 Docking stations with USB interface
oHL-DS-NT3: receptacle for AC adapter, one USB port and one RS485 port (multi-drop).
oHL-DS-U2: receptacle for AC adapter, one USB port, one RS485 port (multi-drop), four
probe inputs (HygroClip or analog probe with voltage output signal), one connector for up
to two logical input signals.
oHL-DS-U2-420: same as HL-DS-U2 but designed for analog probes with a 4-20 mA
output signal. Each probe input uses an internal 150 Ohm resistor to convert 4…20 mA to
600…3000 mV (nominal).
oHL-DS-PT2: receptacle for AC adapter, one USB port, one RS485 port (multi-drop
networking), four connectors for RTD probe (direct 4-wire connection), one connector for
up to two logical input signals.
oHL-DS-R1: receptacle for AC adapter, one USB port, one RS485 port (multi-drop
networking), one connector for up to two logical input signals and two independent relay
output connectors.
3.1.4 Docking stations with wired Ethernet interface
Note: with any of the following models, use an extension cable to separate all probes from either
the HygroLog HL-NT or docking station so as to avoid measurement errors due to self-heating by
the docking station.
oHL-DS-NT4: receptacle for AC adapter, one RJ45 connector (Ethernet), one RS485 port
(multi-drop) and one connector for up to two logical input signals.
oHL-DS-NT4-WEB: same as HL-DS-NT4 but with an internal web server that can be
accessed with a web browser.
oHL-DS-U4: receptacle for AC adapter, one RJ45 connector (Ethernet), one RS485 port
(multi-drop), four probe inputs (HygroClip or analog probe with voltage output signal), one
connector for up to two logical input signals.
oHL-DS-U4-WEB: same as HL-DS-U4 but with an internal web server that can be
accessed with a web browser.
oHL-DS-U4-420: same as HL-DS-U4 but designed for analog probes with a 4-20 mA
output signal. Each probe input uses an internal 150 Ohm resistor to convert 4…20 mA to
600…3000 mV (nominal).
oHL-DS-U4-420-WEB: same as HL-DS-U4-420 but with an internal web server that can
be accessed with a web browser.

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oHL-DS-PT4: receptacle for AC adapter, one RJ45 connector (Ethernet), one RS485 port
(multi-drop networking), two connectors for RTD probe (direct 4-wire connection), one
connector for up to two logical input signals.
3.1.5 Docking stations with wireless Ethernet interface
Note: with any of the following models, use an extension cable to separate all probes from either
the HygroLog HL-NT or docking station so as to avoid measurement errors due to self-heating by
the docking station.
oHL-DS-NT4-WL: receptacle for AC adapter, WLAN transceiver, one RS485 port (multi-
drop) and one connector for up to two logical input signals.
oHL-DS-U4-WL: receptacle for AC adapter, WLAN transceiver, one RS485 port (multi-
drop), two probe inputs (HygroClip 2 or analog probe with voltage output signal), one
connector for up to two logical input signals.
oHL-DS-U4-WEB-WL: same as HL-DS-U4-WL but with an internal web server that can be
accessed with a web browser.
oHL-DS-PT4-WL: receptacle for AC adapter, WLAN transceiver, one RS485 port (multi-
drop networking), two connectors for RTD probe (direct 4-wire connection), one
connector for up to two logical input signals.
Network Interface –Wireless LAN
Standard
IEEE 802.11b
Frequency
2.4 GHz
Data Rate
Up to 11 Mbps with automatic fallback
Modulation
CCK (11/5.5 Mbps), DQPSK (2 Mbps), DBPSK (1 Mbps)
Typical Transmit Power
16 dBm
Receive Sensitivity
-52 dBm @ 11 Mbps
Connector
1 x RP-5MA
WLAN Security
WEP (Wired Equivalent Privacy)
64 / 128-bit encryption (RCA)
WPA / WPA2 / 802.11i
128-bit TKIP/CCMPA(AES) encryption
Enterprise mode (802.1X); LEAP (WEP only), PEAP,
TTLS, TLS; EAP-FAST, GTC, MD5, OTP, PAP, CHAP,
MSCHAP, MSCHAPV2, TTLS-MSCHAPV2
Pre-shared key mode (PSK/Personal)
Note: The WLAN security of docking station HL-DS-U4-WEB-WL (with internal web browser) is
limited to WEP with 64-bit encryption (no WPA).

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3.2 Installation
Installation is the same for all models of docking station.
To mount the docking station to a wall, use
the two holes shown on the right. The
HygroLog NT can then be attached to the
docking station as explained below.
To attach the HygroLog NT to the
docking station:
Place the HygroLog NT on the
docking station so as to match the
two areas [A]. Press lightly one
against the other and secure the
assembly with threaded pin [B].
When the docking station is
mounted on a wall, a small
padlock (not shown) may be put
through pin [B] to prevent removal
of the HygroLog NT from the
docking station.
[B]
[B]
[A]