ROTRONIC HC2-AW-USB User Manual

Measurement stations hc2-aw-(usb)

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ROTRONIC AG, CH-8303 Bassersdorf
Tel. +41 44 838 11 44, www.rotronic.com
ROTRONIC Messgeräte GmbH, D-76275 Ettlingen
Tel. +49 7243 383 250, Fax +49 7243 383 260, www.rotronic.de
ROTRONIC SARL, 56, F - 77183 Croissy Beaubourg
Tél. +33 1 60 95 07 10, www.rotronic.fr
ROTRONIC Italia srl

,

I- 20157 Milano

Tel. +39 2 39 00 71 90, Fax (+39) 02 33 27 62 99, www.rotronic.it
ROTRONIC Instruments (UK) Ltd, Crompton Fields,
Phone +44 1293 571000, www.rotronic.co.uk
ROTRONIC Instrument Corp, NY 11788, USA
Phone +1 631 427-3898, www.rotronic-usa.com
ROTRONIC South East Asia Pte Ltd, Singapore 339156
Phone +65 6294 6065, www.rotronic.com.sg
ROTRONIC Shanghai Rep. Office, Shanghai 200233, China
Phone +86 40 08162018, www.rotronic.cn

MEASUREMENT STATIONS HC2-AW-(USB)

Introduction
The ROTRONIC probe type HC2-AW-(USB) measures
the humidity and the temperature of hygroscopic
products. The digital probe signal is processed by
an indicator such as the HygroLab C1 or the HP23-
AW-A, or from a pc (HC2-AW-USB).

The desired scale, 0…100 %rh equilibrium humidity or 0…1 Aw water activity, can be selected
through the indicator.

Measurement arrangement
For each measurement, a sample cup is necessary.
Exception: For the measurement of paper, cardboard and other similar products simply put the
probe on the sample.

Measurement without temperature control
The whole measuring system, probe + sample cup + sample, adapts to the ambient temperature.

Probe for humidity and temperature

Short InStructIon Manual

Probe

Sample cup item no.: WP-14-S / WP-40)

Sample

Measurement with temperature control
The whole measuring system is temperature stabilized by the connected water circulator.

Water circulation

Water circulation

recommendation
The chosen temperature should not deviate by more than ±5 °C from the ambient temperature.
Reason: The influence of the ambient temperature on the measuring equipment can not completely
be avoided by the temperature control if the temperature difference is too high.

Measurement of paper sheets, cardboard sheets etc.
The use of a sample cup is not necessary. Place the probe directly onto the sheet.

Starting up hc2-aW-uSB
The software HW4 professional with AW-Quick function must be installed probarly. For detailed
information regarding the installation and handling of the HW4 please refer to the software manual
(E-M-HC2-AW-USB-Vxx). Connect the HC2-AW-USB via USB interface to the pc. The pc powers the
HC2-AW probe, press the power button to switch the probe on. The red LED starts to illuminate as
soon the HC2-AW is powered up and has made connection with the indicator.

Starting up hc2-aW
Connect the probe cable with the indicator. The indicator powers the HC2-AW probe, press the power
button to switch the probe on. The red LED starts to illuminate as soon the HC2-AW is powered up
and has made connection with the indicator.

General guidelines
To make accurate and reproducible measurement, follow the following general guidelines to
measure water activity:
• Measure water activity only in rooms with constant temperature; Ideal are rooms with small

daily and yearly temperature variations. Avoid heating of the measuring equipment by sun
radiation or radiators, draught, body radiation etc.

• Put the samples into the disposable sample cup, and put the lid on it. The probe and the sample

must stay in the same room for acclimation (normally room temperature).

A error, which occurs very often in the field is putting the sample a night before the measurement

will be done into the fridge without acclimation. A other error is to measure a sample which
comes directly from production.

Use a climate camber to measure water activity on a other temperature, then the ambient

temperature. Set the desired temperature and put the probe and sample into it.

• Avoiding warming up the probe and sample through body heat. Do not hold not to long in your

hands.

• Check the proper connection between the probe and the indicator. The red LED illuminates

when both, the power and the communication are correct.

Check seal of the o-ring before every
measurement.

Measure

Put the sample into the sample cup.

To avoid cross-contamination do not fill more then up to the fill line.

• Put the probe immediately on the sample cup after having filled in the sample in order to avoid

humidity exchange with the ambient. The measurement time may vary depends on the probe.
Humidity and temperature value are ready to read, when the values are stable for at least
1-2 minutes. Devices with trend indicators will show a stable value with two arrows.

Sources of errors
• Temperature influence; for instance unsuitable measuring site; body radiation etc.
• Dirty filter or O-ring
• The accuracy of the probe is outside the admissible limits; in this case the probe has to be

checked (calibration / adjustment).

• The probes contain chemicals, which cause a drift or destroy the humidity sensor. The sensor

insensitive against chemicals, as long the allowed concentration (continuous operation) will
not be exceeded.

Full line

PS40

PS14

Pollutant

Formula

Max.Workplace

Concentration

Allowed Concentration

Continuous Operation

(ppm)

(mg/m

3

)

(ppm)

(mg/m

3

)

Acetic acid

CH3COOH

10

25

800

2000

Acetone

CH3COCH3

1000

2400

3300

8000

Ammonia

NH3

25

18

5500

4000

2-Butanone (MEK)

C2H5COCH3

200

590

3300

8000

Chlorine

Cl2

0.5

1.5

0.7

2

Ethanol

C2H5OH

1000

1900

3500

6000

Ethyl acetate

CH3COOC2H5

400

1400

4000

15000

Ethylene glycol

HOCH2CH2OH

100

260

1200

3000

Ethylene oxide

C2H4O

3

3

Formaldehyde

HCHO

1

1.2

2400

3000

Hydrochloric acid

HCl

5

7

300

500

Hydrogen sulfide

H2S

10

15

350

500

Isopropanol

(CH3)2CHOH

400

980

4800

12000

Methanol

CH3OH

200

260

3500

6000

Nitrogen oxides

NOx

5

9

5

9

Ozone

O3

0.1

0.2

0.5

1

Petrol

300

1200

150000

Sulfur dioxide

SO2

5

13

5

13

Toluene / Xylene

C6H5CH3

100

380

1300

5000

Periodic calibration of the probe
Both the Pt100 RTD temperature sensor and the corresponding electronics are very stable and do
not normally need to be changed or calibrated after factory calibration. The long term stability of the
ROTRONIC Hygromer humidity probes is typically better than 1 %rh per year. For maximum accuracy
we recommend calibration of the probe about every 6 to 12 months. More frequent calibration
can be necessary in applications where the sensor is exposed to pollutants. The calibration can
be performed by the user himself on site or in the laboratory / workshop. For routine calibrations
the probe should be checked at least at two points, better at three points. The electronics of the
HC2-AW-(USB) do not require calibration in the field. The electronics can not be repaired in the
field and should be returned to the manufacturer in the case of problems.

calibration instruction with rotronIc humidity standard
Generally the following applies:
• Room temperature: 23 °C ±2K
• Instruments, calibrating device and the humidity standard must be at the same tem-

perature. 1K temperature difference between the humidity standard and sensor result in
6 %rh humidity error

• No draughts in the calibration room
• No direct sunshine
• The values of the humidity standards apply at 23 °C
• If the temperature is different from the standard temperature of 23 °C, the corresponding value

of the humidity standard has to be taken into account

recommended calibration values
We recommend to calibrate the HC2-AW-(USB) at 10, 35 and 80 %rh.

Preparation
• For the calibration an indicator with UART interface is needed (HP23-AW)
Make sure the probe is connected to the device. (red LED illuminates)
• Place a textile pad in the disposable sample cup

handling
Hold the ampoule of the selected humidity standard at the neck and bring the entire contents into
the further, lower part of the ampoule by swinging or lightly tapping against the glass. Break the
ampoule at the marked line and empty it completely on the centre of the textile pad while tapping
it lightly. Align the probe so that the opening for the lid points downwards. Screw on the lid with
calibration solution and switch on the HC2-AW-(USB).

adaption time
The time to reach the humidity equilibrium depends upon the humidity standard.

0.5 to 65 %rh

45 min.

65 %rh to 94.9 %rh

60 min.

>95 %rh

120 min.

Start to calibrate taking first the lower values and go up.

calibration
The HC2-AW-(USB) is ready for calibration after the adaption time. The calibration procedure var-
ies from indicator to indicator, for proper operation refer to the corresponding indicator manual.
After every calibration the textile pad and the deposable cup must be renewed and the lid washed
out with water and well dried.
For the calibration with further humidity standards, repeat the calibration steps.

The textile pads are only for onetime using, and can not be used twice.

adjustment
Follow the same procedure as by calibrating the HC2-AW-(USB), only the procedure in the indica-
tor is different. Refer to the corresponding manual.

contamination
Contaminated filters may cause measuring errors and prolong the measuring time. Clean the filter
periodically or, if necessary, replace it depending upon the degree of contamination. In order not
to damage the sensors, remove the filter for cleaning. Clean the filter with soap water, alcohol
or a cleaning agent suitable for removing the contamination and rinse it thoroughly at the end
with water. Do not install the filter until it is completely dry. Replace filters which can no longer
be cleaned by new ones. Should the sensors be severely contaminated despite of the protecting
filter, then we recommend having these replaced by our service department.

accessories and spare parts
Accessories: Disposable sample cup made out of polystrol:

- For cup holder with 14mm fill level

Order code PS-14 (One bag contains 100pcs)

- For cup holder with 40mm fill level

Order code PS-40 (One bag contains 100pcs)

Spare parts: Spare filter including safety ring: order code ET-W24-Set

technical data
Operating ranges:

Humidity 0...1 aw / 0…100 %rh

Temperature -40…85 °C

Output signal:
HC2-AW:

Digital UART

HC2-AW-USB:

USB

Accuracy at 23 °C:

Humidity ±0.008 aw / ±0.8 %rh /

Temperature ±0.1K

Long-term stability:

< 1 %rh / year (Normal conditions)

Factory adjustment:

Adjustment at 23 °C, 10, 35 and 80 rh%

Connector:

Standard HC2-connector

Cable length:
HC2-AW:

1 m

HC2-AW-USB:

3 m

Filter:

wire mesh

Weight:

Approx. 540 gr.

Dimensions:

60mm /

∅ 68mm

System requirements hc2-WIn-uSB
Processor:

Pentium 1 GHz

RAM:

512 MB

Monitor:

SVGA, 1280 x 960 colours 65535

Hard disk HW4:

50 MB

NET2:

280 MB

Operating system:

Windows XP Service Pack 2, Windows 2000 Service Pack 3,

Windows Server 2003, Windows Vista, Windows7

Connection:

one free USB port

Probe

Sample cup
item no.: WP-40TH

Probe

Disposable sample
containers (PS-14/PS-40)

operation display
As soon as the red LED is lit, the device is ready.

Power on/oFF
Press this button to switch the device on or off.

Disposable sample
containers (PS-14/PS-40)

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