rotronic HC2-AW-USB Water Activity and Temperature Probe User Guide

rotronic HC2-AW-USB Water Activity and Temperature Probe

Instruction Manual

Applicability:
This manual applies to the HC2-AW-USB probe with firmware version 1.x (RoPCB firmware), where 1.x can be 1.8, 1.9, etc. Changes to the last digit of the version number reflect minor firmware changes that do not affect the manner in which the probe should be operated.
Note: this manual has been updated to reflect changes made with the introduction of version 3.2.0 of the ROTRONIC HW4 software. Software screenshots appearing in this manual may not apply to previous versions of HW4.

Overview

The HC2-AW-USB is a digital humidity-temperature probe based on the AirChip 3000 technology. .
The HC2-AW-USB probe plugs directly to the USB port of a PC running the HW4 software (Professional Edition with AwQuick, version 3.0.1 or higher) and is designed strictly for PC-based water activity measurement of liquids, pastes, powders and products in chunks.
The ability for the user to easily update the AirChip 3000 firmware means that the HC2-AW-USB probe can be kept up-to-date regarding any future functionality improvement.

Dimensional drawing

General description

Power supply
The HC2-AW-USB probe is directly powered from the USB port of a PC (see below). When connected to a USB port, the probe can be powered or unpowered by pressing on the red button ON / OFF located on top of the probe. The red LED located next to the ON / OFF button is lit when the probe is powered.
Nominal values of a USB port: 5 VDC, 100 mA

Measured parameters

The HC2-AW-USB probe measures water activity with a ROTRONIC Hygromer® capacitive sensor and temperature with a Pt100 RTD.

Digital interface

The HC2 probe features a USB interface that allows two-way communication between a PC and the probe.

Cable and connector

The HC2-AW-USB is equipped with a hard-wired cable (length: 3 m / 9.8 ft”) ended with a standard USB connector.

Sensor protection (dust filter)

The sensors of the HC2-AW-USB probe are protected with a wire mesh dust filter held in place by a snap-ring

Required accessories

Use of the HC2-AW-USB probe requires the following:
PC or Laptop
The following are the minimum values required of the PC or laptop. It is highly recommended to exceed these values.

•  Processor: 1 GHz
•  RAM: 512 MB
•  Available hard disk space: 50 MB
• Monitor: SVGA, 1280 x 960, 65535 colors
• One free USB port

Operating system: Windows XP Service Pack 2 or Vista, Windows 7 with the Microsoft .NET framework
(version 2.0 or higher) installed.
HW4 Software Professional Edition with AwQuick
HW4 Professional with AwQuick is a special version of HW4 Professional designed to facilitate measurement of the water activity (Aw) of foods, pharmaceuticals, etc. This version includes all the features of the regular HW4 Professional Edition. Two modes are available for measuring water activity: AwE and AwQuick. Both modes can be used with any of our instruments. In the AwE mode, HW4 monitors the natural equilibration of the product being measured and automatically stops the measurement process when equilibrium is reached. With most products, natural equilibrium requires from 45 to 90 minutes. The quick mode reduces the time required to measure water activity to a few minutes, usually with almost the same accuracy as the AwE mode.
ROTRONIC USB driver
Communication between the HC2-AW-USB probe and the HW4 PC requires the ROTRONIC USB driver to be installed on the PC. The driver is included in the HW4 CD-ROM
Sample holder and disposable sample cups

WP-40S sample holder with removable depth reduction insert. The PS-14 cups (shallow) are suitable for calibrating the probe with the Rotronic certified humidity standards or with saturated salt solutions. In general, use the shallow cups for a liquid, a paste or a powder. Use the PS-40 (deep) sample cups for products in bulk (large chunks).

Operation

Initial steps
Note: The HC2-AW-UBS probe is designed for use with a PC or laptop running the HW4 software Professional Edition with AwQuick (version 3.1 or higher). For detailed instructions regarding installing and using the HW4 software see the following documents:

• E-M-HW4v3-Main
• E-M-HW4v3-F2-020

On your PC, use Control Panel to verify that the Microsoft .Net Framework is installed:

•  Windows XP: use Control Panel and Add or Remove Programs
•  Vista or Windows 7: Control Panel > Programs and Features.

If the framework is not already installed, install it from the HW4 CD. Note that you will need to restart your PC after installing the framework.

•  Install the HW4 software
•  Make sure that HW4 is not running. Connect the HC2-AW-USB probe to the USB port of your PC. Check that the red LED on top of the probe is lit. This indicates that the probe is being powered. If necessary, power the probe by pressing once on the red button located on top of the probe. When the red LED is not lit, the probe is not powered and the PC is not receiving a signal from the probe. When asked by Windows point to the ROTRONIC USB driver (located in the HW4 installation folder, subfolder USB_driver)
•  Start HW4. In the HW4 main menu bar click on Devices and Groups > Search for Master Devices >USB Masters. After being discovered by HW4, the probe appears in the left pane of the HW4 main screen (device tree). Select the probe with the mouse to make the values currently measured by the probe appear in the right pane of the HW4 main screen.

Preparation of the product samples

The HC2-AW-USB probe is designed for use with the WP-40S sample holder with a removable depth reduction insert.

The WP-40S sample holder can be used with two different sizes of disposable sample cups (PS-14: shallow / PS-40: deep). Use the shallow sample cups (PS-14) together with the depth reduction insert. The PS-14 cups are suitable for calibrating the probe with the Rotronic certified humidity standards or with saturated salt solutions. In general, use the shallow cups for a liquid, a paste or a powder. Use the PS-40 deep sample cups for products in bulk (large chunks). The disposable sample cups serve two purposes:

• Provide a means of storing product samples prior to measurements so that they can come to the same temperature as the probe.
•  Prevent contamination across samples.

Prior to measurements, fill a number of disposable sample cup with the products to be measured. Usually, filling up to 1/3 of the cup is sufficient. To avoid soiling the probe, do not fill the cup above the fill line (see below).

Additional guidelines

• Measure water activity only in a temperature-stable area. This is an essential requirement! Do not measure on a bench that is located near a heater, an AC vent or an open window. Avoid direct exposure of the probe and/or product samples to sunlight (heating effect). For best accuracy, the temperature should not change by more than 0.01°C / minute (0.0075 °C / minute in the case of a product with a water activity > 0.80 aw)
•  Prior to measurements, place each product sample in a disposable sample cup with the cover on. Place the cups in the same general area as the probe. Allow for sufficient time for the samples to come to the temperature of the probe (usually room temperature). A frequent mistake is to measure product samples which have been kept overnight in a refrigerator without first allowing them to come to room temperature. Another mistake is to measure samples coming straight from a hot manufacturing process. To measure water activity at a temperature other than room temperature, place both the probe and the product samples in an incubator set at the desired temperature.
•  Prior to using the probe, verify the integrity and cleanliness of the sealing O-ring located under the probe
•  Avoid warming up the probe, the sample holder or the product sample by touching or holding for too long in your hand.

Water activity measurement with HW4
Water activity measurement modes
The AwE / AwQuick tab is available only with HW4 Professional with AwQuick. HW4 features two modes for measuring water activity and the name of the tab depends on which mode has been selected.

• AwE mode

In this mode, HW4 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 45 to 60 minutes and can take as long as a couple of hours.

• quick mode:

In the quick mode, HW4 uses an algorithm to project the full equilibrium value (water activity) of the measured product. The measurement is automatically ended and typically requires about 5 minutes.
HW4 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), HW4 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 quick mode is generally within ± 0.005 aw of the measurement that would be obtained by waiting for full equilibration (AwE mode).
Mode selection and settings
To select the mode and to enter or modify the settings to be used in each mode, select Settings and Tools in the HW4 main menu bar. Under Settings and Tools select HW4 Global Settings and select the AwQuick Mode / AwE Mode tab (the name of this tab changes depending on the mode that is currently selected).

Note: the values shown above are the most frequently used.
IMPORTANT: Both the selected mode and its settings apply globally to all instruments and probes.
To select the mode and to enter or modify the settings to be used in each mode, click on the Settings button located on the AwE / AwQuick tab.

Working with individual probes or with a group of probes
Working with individual probes
Probes just discovered by HW4 (HW4 Main Menu Bar > Devices and Groups > Search for Master Devices > USB Masters) are shown individually in the Device Tree.

At any time only one probe can be selected in the Device Tree. After selecting a probe, the user can start measuring water activity with that probe.
HW4 can run several water activity measurements concurrently. Select any probe and start measuring water activity with that probe. Select another probe and start measuring water activity with that other probe. The water activity measurement process (AwQuick or AwE mode) runs independently for each probe. When measuring water activity with several individual probes simultaneously, it is incumbent to the user to change from time to time the probe selected in the Device Tree so as to find out when the measurement is ended.
Note: the bottom of the form has 3 text fields labeled “Batch Number”, “Product Name” and “Comments”. The contents of these fields will appear on the water activity measurement report, assuming that the user decides to generate such a report. To customize the contents of these fields for each probe, wait until one of the probes is done and enter a text in each field just before clicking on the “Generate report” button. Select another probe and proceed in the same manner.
Working with a group of probes
Probes that have been discovered by HW4 can be put into a group created by the user as illustrated below:

Working with a group of probes offers the convenience of monitoring all probes at the same time. However, the contents text fields labeled “Batch Number”, “Product Name” and “Comments” are shared by all probes within the group and cannot be customized for each individual probe.

 Measurement procedure (AwQuick or AwE Mode)

1.  Select an individual probe or a group of probes in the Device Tree (left pane of the HW4 main screen)
2.  In the right pane of the HW4 main screen, select the AwE / AwQuick tab (the label of this tab changes depending on which mode is currently selected in the HW4 Global Settings). Note that the right pane is slightly different depending on whether an individual probe or a group of probe has been selected in the Device Tree.
3.  Select the probe or probes to be used for the measurement by clicking on the box located to the left of the probe (a checkmark appears when the probe is selected).
4.  To start the measurement, click on the Start button located at the bottom of the form. A small blue symbol appears to the left of the probe to indicate that the measurement is in progress. After a while trend indicators also appear next to the water activity and temperature readings.
5.  When HW4 detects equilibrium condition, the measurement ends automatically and the symbol to the left of the probe changes to green. The result appears in the “Water Activity” column.
6. 6. Optional: at this time you may want to enter a Batch Number, a Product Name and Comments in the fields located at the bottom of the form. This information will appear in the water activity measurement report should you choose to generate such a report.
7. Optional: click on the button labeled “Generate report” to generate a water activity report.
8. The process is ended by clicking on the Stop button located at the bottom of the form. At this time a new measurement can be started.

Water activity measurement report

NOTE: Generate and save Protocols” must be enabled in HW4 Global Settings

Events tab
Prior to clicking on the Stop button, click on the “Generate Report” button to generate a measurement report. HW4 opens a dialog box that allows the user to specify a file name and a location. The report is saved as a text file (extension txt).

Use the report menu bar to sign and/or print the report.

Signing the report
Select “Sign document” from the file menu to add your HW4 user name and a comment text to the report. For authentication purposes, you will need to enter your password.

A new section is inserted at the bottom of the report:

Maintenance

Cleaning or replacing the dust filter
Depending on the conditions of measurement, the wire mesh dust filter (model W24) should be checked from time to time. Corroded, discolored or clogged filters should be replaced.
Periodic calibration check
Both the Pt100 RTD temperature sensor and associated electronics are very stable and should not require any calibration after the initial factory adjustment.
Long term stability of the ROTRONIC Hygromer humidity sensor is typically better than 1 %RH per year. For maximum accuracy, calibration of the probe should be verified every 6 to 12 months. Applications, where the probe is exposed to contaminants, may require more frequent verifications. Calibration and adjustment of the HC2 probe is done with a PC with the HW4 software installed (version 3.0.1 or higher).
Procedure for adjusting the HC2 probe with the ROTRONIC HW4 software:

•  Connect the HC2-AW-USB probe to the HW4 PC as explained in the HW4 manual E-M-HW4v3-Main
• Start HW4 software on the PC and search for the HC2 probe. (HW4 Main Menu Bar > Devices and Groups > Search for USB masters.
• After finding the HC2-AW-USB probe with HW4, expand the device tree to see the probe functions and select Probe Adjustment.
• For further instructions see HW4 manual E-M-HW4v3-A2-001

Validation of the output signals transmission
If so desired, the transmission of the HC2-AW-USB 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.

Firmware updates

Firmware updates will be available on the ROTRONIC website for downloading. Firmware files are given a name that shows both to which device the file applies and the version number of the firmware. All firmware files have the extension HEX
Procedure for updating the firmware:

• Connect the HC2-AW-USB probe to the HW4 PC as explained in the HW4 manual E-M-HW4v3-Main
•  Copy the firmware update file from the ROTRONIC website to the PC.
• Start HW4 software on the PC and search for the HC2 probe. (HW4 Main Menu Bar > Devices and Groups > Search for USB masters.
• After finding the HC2-AW-USB probe, expand the device tree to see the probe functions. Select Device Manager. In the Device Manager menu bar select Tools > Firmware Update. For instructions see document E-M-HW4v3-F2-020

Specifications

General|
---|---
Device type| Humidity temperature probe
Mechanical configuration| See models
Power supply and connections

Supply voltage (VDD)| 5 V (supplied from a USB port to which the probe is connected)
Nominal current consumption| < 25 mA
Humidity measurement|
---|---
Sensor| ROTRONIC Hygromer ® WA-1
Measuring range| 0…100 %RH (0.000 to 1.000 aw)
Measurement accuracy at 23 °C| ±0.8 %RH (w. standard adjustment profile)
Repeatability| 0.3 %RH
Long term stability| < 1 %RH / year
Temperature measurement|
---|---
Sensor| Pt100 RTD, IEC 751 1/3 class B
Measuring range| -40…85 °C (-40…185 °F)
Measurement accuracy at 23 °C| ±0.1 °C
Repeatability| 0.05°C
Long term stability| < 0.1°C / year
Start-up time and data refresh rate|
---|---
Start-up time| 1.5s (typical)
Data refresh rate| 1.0s (typical)
Digital interface

Interface type| USB 2.0
Signal cable length| 3 m (9.8.4 ft)

General specifications

Housing material| Barrel: aluminum (top) , stainless steel (bottom)
Dust filter material| Stainless steel wire mesh
Physical dimensions| 60 mm (H) x 68 mm (diameter)
Probe cable length| 0.95 m (37.5”)
Weight| approx. 541 g (1 lb 3.1 oz)
Conformity to standards|
---|---

CE / EMC immunity

| EMC Directive 2004/108/EG: EN 61000-6-1: 2001, EN 61000-6-2: 2005

EN 61000-6-3: 2005, EN 61000-6-4: 2001 + A11

No measurement is possible in the presence of electromagnetic emissions

Solder type| Lead free (RoHS directive)
FDA / GAMP directives| compatible
Environmental limits|
---|---
Storage and transit| -40…+85 °C / 0…100 %RH, non condensing
Document File Name| Contents
---|---
E-M-HW4v3-DIR| List of the HW4 manuals
E-M-HW4v3-Main| HW4 software version 3: General instructions and functions common to all devices
E-M-HW4v3-F2-020| HW4 software version 3: HC2-AW-USB Water Activity Probe Device configuration and AirChip 3000 functions
E-M-HW4v3-A2-001| HW4 software version 3: Probe Adjustment function AirChip 3000 devices
E-M-HW4v3-DR-001| HW4 software version 3: Data Recording Function AirChip 3000 Devices
E-M-CalBasics| Temperature and humidity adjustment basics Instructions for using the ROTRONIC humidity standards

Note: All document file names have an extension corresponding to the document release number (example of a first release: E-M-HW4v3-Main_10). This extension is not shown in the above table.

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