Rotronic AwTherm User manual

E-M-AwTherm-V1.1
Rotronic AG
Bassersdorf, Switzerland
Document code Unit
AwTherm: Water Activity at Controlled Temperature Instruction Manual Version 1.1
Document Type
Document title
Instruction Manual
© 2009-2010; Rotronic AG E-M-AwTherm v1.1

E-M-AwTherm-V1.1
Rotronic AG
Bassersdorf, Switzerland
Document code Unit
AwTherm: Important notice before first use
Advisory Notice
Document Type
Document title
Contents of the Standard Supply Package:
•AwTherm stabilised temperature water activity meter with either PS-14 or PS-40 sample
cup holder
•HW4-P-Quick-V3 software code sticker
•MicroUSB cable for connection to HW4
•MicroUSB memory stick including HW4 and User Manual
•Power cables for UK or US/EU/CH
© 2009-2010; Rotronic AG E-M-AwTherm v1.1

E-M-AwTherm-V1.1
Rotronic AG
Bassersdorf, Switzerland
Document code Unit
AwTherm: Table of Contents
Table of Contents
Document Type
Document title
1Scope of Document................................................................................................................1
1.1 Introducing the AwTherm......................................................................................................1
1.2 Measuring Technology...........................................................................................................1
1.3 Calibration..............................................................................................................................1
2Setting up the AwTherm ........................................................................................................2
2.1 Physical Location....................................................................................................................2
2.2 Electrical Supply .....................................................................................................................2
2.3 AwTherm Assembly ...............................................................................................................4
2.4 Sample cup size......................................................................................................................5
3AwTherm Operation ..............................................................................................................6
3.1 Switching On ..........................................................................................................................6
3.2 AwTherm Interface ................................................................................................................7
3.2.1 Basic Navigation ........................................................................................................8
3.2.2 Main Menu................................................................................................................9
3.2.3 AwTherm Settings ...................................................................................................10
3.2.4 Setting the AwTherm Set Point Temperature.........................................................13
3.3 Making Measurements ........................................................................................................14
3.3.1 Starting a measurement run ...................................................................................16
3.3.2 AwE Mode ...............................................................................................................17
3.3.3 AwQ Mode ..............................................................................................................18
3.4 Switching off the AwTherm .................................................................................................19
3.5 Preparing the Unit for Transit or Storage ............................................................................20
4Sample preparation .............................................................................................................21
4.1 Protection from environment..............................................................................................21
4.2 Sample size and temperature equilibration time ................................................................21
4.3 Best Practices.......................................................................................................................21
4.3.1 Precondition samples to measurement temperature ............................................21
4.3.2 Avoid condensation.................................................................................................21
4.3.3 Define procedures...................................................................................................22
5PC Software.........................................................................................................................22
5.1 HW4 .....................................................................................................................................22
5.2 HW4 Support........................................................................................................................22
6Servicing and Maintenance ..................................................................................................23
6.1 AwTherm Calibration ...........................................................................................................23
6.1.1 Remove measuring head for calibration.................................................................23
6.1.2 Calibrate in Hygrogen2............................................................................................26
6.2 AwTherm Cleaning...............................................................................................................26
6.2.1 External surfaces.....................................................................................................26
6.2.2 Filter ........................................................................................................................26
6.2.3 Chamber..................................................................................................................27
6.3 Annual Servicing of AwTherm..............................................................................................28
6.4 Firmware Updates................................................................................................................29
A1: AwTherm / Screen Messages.................................................................................................31
A2: AwTherm Specifications ........................................................................................................32
A3: AwTherm Order Codes ..........................................................................................................33
© 2012; Rotronic AG E-M-AwTherm v1.1

E-M-AwTherm-V1.1
Rotronic AG
Bassersdorf, Switzerland
Document code Unit
AwTherm: Table of Contents
Table of Contents
Document Type
Document title
A4: AwTherm Environmental Conditions .....................................................................................33
A5: Electrical Specifications .........................................................................................................33
A6: Battery disposal and replacement .........................................................................................34
B1: AwTherm Warranty Statement..............................................................................................35
B2: Manufacturer & Service Centre Contact Information..............................................................36
© 2012; Rotronic AG E-M-AwTherm v1.1

E-M-AwTherm-V1.1
Rotronic AG
Bassersdorf, Switzerland
Document code Unit
AwTherm: Water Activity at Controlled Temperature
Instruction Manual for Software
Version 1.1
Document Type
Page 1
Document title
1Scope of Document
This instruction manual refers to AwTherm running software version Aw-v1.00. To determine the
software version your instrument is running please refer to the Device Info screen as shown in
Section 3.2.1. Updates are available on www.awtherm.com. This manual refers to the operation,
care and maintenance of the instrument itself, and best practices when making measurements.
For theory, background and further information on water activity, please refer to
www.awtherm.com.
1.1 Introducing the AwTherm
AwTherm is a temperature controlled water activity station – used for determining the water
activity of a sample, maintained at a known temperature. Water activity, which is used as a
measure of product consistency, is a parameter that is strongly dependent on temperature, and so
for consistent, repeatable measurements, it is vital to maintain known and stable thermal
conditions.
AwTherm is based on the same technology as the Rotronic HygroGen2 temperature and humidity
calibration suite of instruments which manipulate forced air to create highly stable thermal
conditions with minimal gradients within the measurement environment.
1.2 Measuring Technology
AwTherm uses a Rotronic HygroClip2 series probe to control and measure conditions.
1.3 Calibration
Calibration is an essential part of any reliable measurement process. AwTherm has a removable
measuring head which can be removed entirely (see Section 6.1.1) for calibration of both Aw and
Temperature parameters against references traceable to National Standards, using for example a
HygroGen2 temperature and humidity calibration system. The removed head is attached to the
HygroGen2 or a PC running Rotronic HW4 software (see section 5) using a special cable (not
supplied). Alternatively, the Aw parameter only can be calibrated in situ using Rotronic Calibration
Salts and adjusted using HW4 running on a PC connected to the AwTherm via its micro USB port.
© 2012; Rotronic AG E-M-AwTherm v1.1

E-M-AwTherm-V1.1
Rotronic AG
Bassersdorf, Switzerland
Document code Unit
AwTherm: Water Activity at Controlled Temperature
Instruction Manual for Software
Version 1.1
Document Type
Page 2
Document title
2Setting up the AwTherm
2.1 Physical Location
To ensure correct operation please ensure that:
1. The unit is level and stable;
2. There is at least 15 mm clearance underneath and at least 100 mm at the back of the unit
to enable adequate air flow;
2.2 Electrical Supply
Power Isolation
The unit is supplied with a mains cord set. The unit should be disconnected from the electrical
supply before the unit is moved, cleaned or has water added or removed.
Earthing
This unit must be earthed. Provision for the safety earth is made through the electrical mains
connection (Figure 2, item 5) to which all parts of the unit requiring earthing are internally
connected. An earthed electrical supply is required.
Earth Leakage Current
Due to RF filtering there is an earth leakage current, within the limits specified in EN 61010-
1:2001. This may affect mains power circuits protected by Residual Current Device (RCD) or
Ground Fault Detector (GFD) type circuit breakers (particularly if used in multiples or with other
equipment with an earth leakage current on the same supply circuit).
Over Current Protection
To protect the internal circuitry against excess currents, the mains supply to the unit must be
connected with the mains cord set provided with the unit and to an appropriate mains supply.
Voltage Rating
The unit is designed to work within the limits of a 110-230 VAC 50-60 Hz mains supply with voltage
fluctuations up to ± 10% of the nominal voltage. The unit is rated impulse withstand (over voltage)
category II of IEC 60364-4-443. Where occasional voltage transients over 2.5 kV are expected or
measured, it may be necessary that the power installation to the unit includes a transient limiting
device.
© 2012; Rotronic AG E-M-AwTherm v1.1

E-M-AwTherm-V1.1
Rotronic AG
Bassersdorf, Switzerland
Document code Unit
AwTherm: Water Activity at Controlled Temperature
Instruction Manual for Software
Version 1.1
Document Type
Page 3
Document title
Mains Filtration
If there is risk of power spikes or breaks, it is recommended that an Uninterruptable Power Supply
(UPS) is used to provide continued power and mains filtration. This should be rated according to
the AwTherm power specifications (see Appendix A5: Electrical Specifications) and the time
required to run/shutdown during power outage.
Conductive Pollution
The unit is rated Pollution Degree 2 and must not be operated in environments where conductive
pollutants (for example carbon) may enter the unit (this includes excessive moisture ingress).
© 2012; Rotronic AG E-M-AwTherm v1.1

E-M-AwTherm-V1.1
Rotronic AG
Bassersdorf, Switzerland
Document code Unit
AwTherm: Water Activity at Controlled Temperature
Instruction Manual for Software
Version 1.1
Document Type
Page 4
Document title
2.3 AwTherm Assembly
Figure 2-1 - AwTherm Assembly (with lid open, front and rear view)
1) Lid
2) Removable measuring head
3) Sensor
4) Rubber seal
5) Electrical mains connection
6) Heat pump
7) Air flow sleeve
8) Sample cup
9) PSU fan outlet Heat pump fan outlet
10) Heat pump fan outlet
11) Micro USB port
12) Sample cup holder (PS14 or PS40)
13) Touch buttons
14) Screen
Figure 2-2 Sample Chamber
© 2012; Rotronic AG E-M-AwTherm v1.1

E-M-AwTherm-V1.1
Rotronic AG
Bassersdorf, Switzerland
Document code Unit
AwTherm: Water Activity at Controlled Temperature
Instruction Manual for Software
Version 1.1
Document Type
Page 5
Document title
15) Touch Button (up)
16) Touch button (down)
17) Touch button (ENTER)
18) Removable heat pump fan filter
2.4 Sample cup size
AwTherm is available in either PS14 (14mm depth) or PS40 (40mm depth) sample cup holder sizes.
Alternative sample cup holders are available as accessories (see Section A3: AwTherm Order
Codes).
Note that sample equilibrium time is dependent on the sample space, and so the selection of
sample cup size should be the smaller PS14 size where possible. For example powders and liquids
would merit selecting the smaller PS14 size; samples that are impractical for this size, e.g. large
seeds and pet foods, would merit the larger PS40 sample cup.
Figure 2-3 AwTherm Assembly (lid closed)
Figure 2-4 Removable filter (heat pump fan)
Figure 2-5 AwTherm Touch Interface
© 2012; Rotronic AG E-M-AwTherm v1.1

E-M-AwTherm-V1.1
Rotronic AG
Bassersdorf, Switzerland
Document code Unit
AwTherm: Water Activity at Controlled Temperature
Instruction Manual for Software
Version 1.1
Document Type
Page 6
Document title
3AwTherm Operation
3.1 Switching On
1. Ensure the electrical mains supply is correctly plugged in and switched on.
2. Switch the unit on by pressing the ENTER button once.
3. The fans within the unit will switch on giving an immediate audible indication the unit is
powered.
4. The loading screen will display (Figure 3-1)
5. The controller will power up and display the Top Level screen (as shown in Figure 3-2).
Figure 3-1 Boot screen
On power up:
•The temperature set-point defaults to the last set value.
•The temperature control defaults to automatic mode (controlling the temperature).
© 2012; Rotronic AG E-M-AwTherm v1.1

E-M-AwTherm-V1.1
Rotronic AG
Bassersdorf, Switzerland
Document code Unit
AwTherm: Water Activity at Controlled Temperature
Instruction Manual for Software
Version 1.1
Document Type
Page 7
Document title
3.2 AwTherm Interface
Figure 3-2 AwTherm Top Level Screen
19) Temperature trend indication
20) Aw trend indication
21) Temperature field
22) Live Aw reading
23) Status field
24) MENU
© 2012; Rotronic AG E-M-AwTherm v1.1

E-M-AwTherm-V1.1
Rotronic AG
Bassersdorf, Switzerland
Document code Unit
AwTherm: Water Activity at Controlled Temperature
Instruction Manual for Software
Version 1.1
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Page 8
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3.2.1 Basic Navigation
The AwTherm interface consists of a Top Level Screen with 3 fields which can be manipulated: (set
point) temperature, status, and device settings (Menu). Pressing the up or down arrow scrolls
through each of these, highlighting each one in turn. To select one, press the ENTER button. The
field will flash, and the functionality activated.
Figure 3-3 Basic Function Navigation
© 2012; Rotronic AG E-M-AwTherm v1.1

E-M-AwTherm-V1.1
Rotronic AG
Bassersdorf, Switzerland
Document code Unit
AwTherm: Water Activity at Controlled Temperature
Instruction Manual for Software
Version 1.1
Document Type
Page 9
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3.2.2 Main Menu
There are a number of AwTherm system and program settings that can be configured. To access
the settings, select MENU and press the ENTER button.
Figure 3-4 Access Device Settings Menu
NB For all menus and sub-menus, to return to the previous screen, scroll down to the RETURN
field and press the ENTER button.
© 2012; Rotronic AG E-M-AwTherm v1.1

E-M-AwTherm-V1.1
Rotronic AG
Bassersdorf, Switzerland
Document code Unit
AwTherm: Water Activity at Controlled Temperature
Instruction Manual for Software
Version 1.1
Document Type
Page 10
Document title
Any adjustable parameter can be selected using the UP/DOWN and ENTER touch buttons in the
same manner as described for basic menu navigation. The parameter can be adjusted using the
UP/DOWN buttons and set by pressing the ENTER button.
Please note, by pressing and holding the up or down arrow keys, the speed of any numeric
incrementation will increase (autoscroll).
3.2.3 AwTherm Settings
i) Device Info displays the serial numbers of the unit itself, the AirChip Sensor and the firmware
version that the AwTherm is running.
Figure 3-5 Device Info
ii) Device Settings; Enable or disable temperature control (on by default), disable the Trend
Indication for temperature (19) and Aw (20) as shown in Figure 6, and configure the Aw measuring
mode: AwE or Aw-Quick (see section , below). Touch buttons can be set to make an audible sound
when activated, contrast adjusted (default optimal setting is 35%), and touchpad sensitivity
adjusted – from a value from 0-5. Please note, if touch pad has poor responsivity, try each
individual setting in turn until best results achieved.
Figure 3-6 Device Settings
© 2012; Rotronic AG E-M-AwTherm v1.1

E-M-AwTherm-V1.1
Rotronic AG
Bassersdorf, Switzerland
Document code Unit
AwTherm: Water Activity at Controlled Temperature
Instruction Manual for Software
Version 1.1
Document Type
Page 11
Document title
iii) Time/Date Settings; Date and time can be set and displayed on the AwTherm (off by default).
Time/date is only displayed for convenience and is not used a part of data logging and therefore is
not crucial to the operation of the instrument. Data logging is performed using Rotronic HW4
software running on an external PC (see Section 5.1).
Please note the date format [DD/MM/YYYY] is fixed and cannot be changed.
Figure 3-7 Time/date Settings
iv) AwE Settings; the AwE Tolerance, Temperature tolerance, and process complete audible beep
volume can be configured here. Further details regarding AwE measurement mode are found in
Section 3.3.2.
Figure 3-8 AwE Settings
© 2012; Rotronic AG E-M-AwTherm v1.1

E-M-AwTherm-V1.1
Rotronic AG
Bassersdorf, Switzerland
Document code Unit
AwTherm: Water Activity at Controlled Temperature
Instruction Manual for Software
Version 1.1
Document Type
Page 12
Document title
v) AwQ Settings; the Aw-Quick dwell time and temperature tolerance, and process complete
audible beep volume can be configured here. Further details regarding AwQ measurement mode
are found in Section 3.3.3.
Figure 3-9 AwQ Settings
vi) Service; the AwTherm firmware can be updated via this menu using a Micro USB drive inserted
into the Micro USB port (11) on the rear of the AwTherm.
Figure 3-10 Service
Select the Update Firmware field and change the NO to YES using the up or down arrow keys and
press ENTER. Further details about updating the firmware are found in Section 6.4. There is also an
indication of the internal CMOS battery condition.
© 2012; Rotronic AG E-M-AwTherm v1.1

E-M-AwTherm-V1.1
Rotronic AG
Bassersdorf, Switzerland
Document code Unit
AwTherm: Water Activity at Controlled Temperature
Instruction Manual for Software
Version 1.1
Document Type
Page 13
Document title
3.2.4 Setting the AwTherm Set Point Temperature
Figure 3-11 AwTherm Top Level Screen
With the Temperature Control parameter turned on (Section 3.2.3), and the lid (1) closed, the
AwTherm will control the temperature of the sample chamber environment (12). The heat pump
(6) controls the temperature of the air which is circulated through the airflow sleeve (7) around
the outside the walls of the sample chamber.
To set the temperature, from the Top Level screen (Figure 3-11), use the up and down arrows to
select the Temperature parameter. Press ENTER; the temperature parameter will flash (Figure 3-
12) and the label will change to SP (set point).
Figure 3-12 Select Temperature parameter
Use the UP/DOWN touch buttons to adjust the value to the desired temperature and press ENTER
to accept it.
© 2012; Rotronic AG E-M-AwTherm v1.1

E-M-AwTherm-V1.1
Rotronic AG
Bassersdorf, Switzerland
Document code Unit
AwTherm: Water Activity at Controlled Temperature
Instruction Manual for Software
Version 1.1
Document Type
Page 14
Document title
Figure 3-13 Define new Set Point Temperature
AwTherm will now control the temperature of the chamber to the new temperature. The time it
takes for the chamber to reach the temperature will depend on the ambient conditions, and the
initial and set point temperatures. Depending on the magnitude of the temperature change
required, the instrument will slightly overshoot, before coming back and stabilising. The Trend
Indicator (19) will show whether the unit is heating or cooling. When stable (to within the defined
AwE/AwQ temperature tolerance – see Section 3.3) the Trend Indicator will display up and down
indicators simultaneously.
Note that the chamber will reach a stable set point temperature before the sample, depending on
the initial temperature of the sample. See Sample Preparation: best practices and operational
considerations (Section 4.3) below for further details and advice.
3.3 Making Measurements
AwTherm features two modes for measuring water activity.
●AwE mode:
In this mode AwTherm monitors the stability of both temperature and humidity. The
measurement is automatically ended as soon as both humidity and temperature reach
equilibrium. The natural (or static) equilibration of most products typically requires from 15 to 60
minutes and can take as long as a couple of hours.
© 2012; Rotronic AG E-M-AwTherm v1.1

E-M-AwTherm-V1.1
Rotronic AG
Bassersdorf, Switzerland
Document code Unit
AwTherm: Water Activity at Controlled Temperature
Instruction Manual for Software
Version 1.1
Document Type
Page 15
Document title
●AwQuick mode:
In the AwQuick mode, AwTherm uses an algorithm to project the full equilibrium value (water
activity) of the measured product. The measurement is automatically ended and typically requires
typically about 5 minutes. AwTherm performs the following tasks:
1) The value of the humidity signal is constantly monitored
2) The stability of the temperature signal is constantly monitored
3) After an initial period of time (dwell time), AwTherm uses the humidity data to project the end
value of the equilibration process (water activity). The measurement ends automatically as soon
as the projected Aw value is stable.
With the dwell time set to 4 minutes, measurements typically require about 5 minutes. When
temperature conditions are stable (both at the product and probe), the measurement obtained
with the AwQuick mode is generally within ± 0.005 aw of the measurement that would be
obtained by waiting for full equilibration (AwE mode).
Aw mode can be selected in Device Settings as described above (Section 3.2.3). Load your sample
into the instrument, following the guidelines as outlined in Section 4.
© 2012; Rotronic AG E-M-AwTherm v1.1

E-M-AwTherm-V1.1
Rotronic AG
Bassersdorf, Switzerland
Document code Unit
AwTherm: Water Activity at Controlled Temperature
Instruction Manual for Software
Version 1.1
Document Type
Page 16
Document title
3.3.1 Starting a measurement run
To start a measurement run, at the Top Level screen, select the status field and press ENTER.
Figure 3-14 Select status field
Then use the UP/DOWN touch buttons to and select START, and then press ENTER.
Figure 3-15 Select START and press ENTER
The measurement run will now begin.
At the end of the run, the AwTherm will sound an audible beep (if so configured, see Section 3.2.3)
and hold the values on the screen, displaying FINISHED in the status field.
The following section describes the operation of each mode, AwE and AwQ as a flowchart.
© 2012; Rotronic AG E-M-AwTherm v1.1