U.S. patent application number 15/149922 was filed with the patent office on 2016-09-01 for mass comparator with removable climate module.
The applicant listed for this patent is Sartorius Lab Instruments GmbH & Co. KG. Invention is credited to Richard ESSER, Thomas FEHLING, Benno GATZEMEIER, Rainer GUNKEL, Falko HILBRUNNER, Heyko HOLST, Sigo MUEHLICH.
Application Number | 20160252388 15/149922 |
Document ID | / |
Family ID | 52991020 |
Filed Date | 2016-09-01 |
United States Patent
Application |
20160252388 |
Kind Code |
A1 |
ESSER; Richard ; et
al. |
September 1, 2016 |
MASS COMPARATOR WITH REMOVABLE CLIMATE MODULE
Abstract
A mass comparator including a weighing chamber (16); a draft
shield (18, 20, 22), which surrounds the weighing chamber; a
climate module (34), which is detachably disposed in the weighing
chamber; a processor (32), a data input unit, and a data
transmission path, over which data is exchanged between the climate
module and the processor. The processor is programmed to use the
air pressure, the air humidity and the air temperature in the
weighing chamber to determine, based on the density of a substance
to be weighed, an air buoyancy of at least one test sample and/or a
buoyancy correction factor. Also disclosed are a climate module
configured to electrically yet detachably couple to a mass
comparator, and a method for operating a mass comparator including
determining the air buoyancy and/or the buoyancy correction
factor.
Inventors: |
ESSER; Richard;
(Bovenden-Eddigehausen, DE) ; HOLST; Heyko;
(Goettingen, DE) ; MUEHLICH; Sigo; (Bovenden,
DE) ; HILBRUNNER; Falko; (Ilmenau, DE) ;
FEHLING; Thomas; (Witzenhausen, DE) ; GATZEMEIER;
Benno; (Goettingen, DE) ; GUNKEL; Rainer;
(Schimberg, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Sartorius Lab Instruments GmbH & Co. KG |
Goettingen |
|
DE |
|
|
Family ID: |
52991020 |
Appl. No.: |
15/149922 |
Filed: |
May 9, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/EP2014/002855 |
Oct 22, 2014 |
|
|
|
15149922 |
|
|
|
|
Current U.S.
Class: |
177/1 |
Current CPC
Class: |
G01G 21/22 20130101;
G01G 23/48 20130101; G01N 9/26 20130101; G05D 11/00 20130101; G01G
19/303 20130101; G01G 21/286 20130101; H01L 21/67 20130101; G01G
17/04 20130101; B01L 3/021 20130101; G01G 23/01 20130101 |
International
Class: |
G01G 21/22 20060101
G01G021/22; G01N 9/26 20060101 G01N009/26; G01G 23/01 20060101
G01G023/01 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 8, 2013 |
DE |
102013018767.2 |
Feb 7, 2014 |
DE |
102014101565.7 |
Claims
1. Mass comparator, comprising: a weighing chamber; a draft shield,
which surrounds the weighing chamber; a climate module, which
comprises an air pressure sensor, an air humidity sensor and an air
temperature sensor, and which is detachably disposed in the
weighing chamber and is configured to mount within and to detach
from the weighing chamber; a processor; a data input unit; and a
data transmission path, over which data is exchanged between the
climate module and the processor, wherein the processor is
programmed to determine, based on a density of a substance to be
weighed, an air buoyancy of at least one test sample and/or a
buoyancy correction factor in accordance with the air pressure, the
air humidity and the air temperature in the weighing chamber.
2. The mass comparator as claimed in claim 1, wherein the data
transmission path comprises an electrical plug-in connection.
3. The mass comparator as claimed in claim 1, wherein the data
transmission path comprises a wireless transmission.
4. The mass comparator as claimed in claim 1, wherein the climate
module further comprises a sensor coupled to the data transmission
unit and configured to determine a degree of ionization in the
weighing chamber.
5. The mass comparator as claimed in claim 1, wherein the climate
module comprises a light sensor, which is coupled to the data
transmission path.
6. Climate module comprising: a detachable coupling configured to
secure the climate module detachably to a mass comparator, a
self-contained modular unit comprising an air pressure sensor, an
air humidity sensor and an air temperature sensor, and a data
transmission path, configured to transmit data from the modular
unit to a processor external to the climate module.
7. The climate module as claimed in claim 6, further comprising an
electronic memory configured to store calibration values and
correction values for the climate module and to be read by an
external reader.
8. The climate module as claimed in claim 6, configured as a
stand-alone unit that is external to mass comparator and that
comprises an I.sup.2C bus configured to connect to a USB port of a
computer.
9. Method for operating a mass comparator that comprises a weighing
chamber, which is separated from a surrounding area by a draft
shield and in which an air pressure sensor, an air humidity sensor,
and an air temperature sensor are disposed, wherein the sensors are
coupled to a processor, and that is configured to weigh a test
sample and at least one reference weight, said method comprising:
determining the air pressure, the air humidity and the air
temperature in the weighing chamber with the sensors; entering a
density of the test sample into the mass comparator; determining an
air buoyancy of at least the test sample and/or a buoyancy
correction factor in accordance with the air pressure, the air
humidity, the air temperature and the density of the test sample;
and determining a corrected, conventional weighing value of the
test sample (B).
10. The method as claimed in claim 9, further comprising
determining a degree of ionization in the weighing chamber; and
outputting an output signal from the processor in accordance with
the degree of ionization.
11. The method as claimed in claim 9, further comprising
determining incident light with a light sensor in the weighing
chamber.
12. The method as claimed in claim 11, further comprising
outputting an output signal from the processor in response to a
predetermined incident light level.
13. The method as claimed in claim 9, wherein at least some of the
sensors are housed in a climate module that is configured to
decouple from a remainder of the mass comparator, further
comprising: storing calibration values and correction values in a
memory of the climate module; and calibrating the mass comparator
after detaching the climate module from the remainder of the mass
comparator.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a Continuation of International Application
PCT/EP2014/002855, which has an international filing date of Oct.
22, 2014, and the disclosure of which is incorporated in its
entirety into the present Continuation by reference. The following
disclosure is also based on and claims the benefit of and priority
under 35 U.S.C. .sctn.119(a) to German Patent Application Nos. DE
10 2013 018 767.2, filed Nov. 8, 2013, and to DE 10 2014 101 565.7,
filed Feb. 7, 2014, which are also incorporated in their respective
entireties into the present Continuation by reference.
FIELD OF THE INVENTION
[0002] The invention relates to a mass comparator and a method for
operating a mass comparator comprising a weighing chamber, which is
separated from the surrounding area by a draft shield. In addition,
the invention relates to a climate module of such a mass
comparator.
BACKGROUND
[0003] Electronic mass comparators, which relate to the present
invention, work with a comparison measurement. A known mass is
compared, as a reference object, with the mass of a test sample in
several weighing steps. Such test samples are, in particular, the
reference masses for other balances. The present invention relates,
in particular, to high resolution electronic mass comparators for
mass comparisons, for example, for the accuracy classes E1 to F2 in
compliance with OIML R 111-1 [OIML=International Organization on
Legal Metrology]. For these mass comparisons the air density, which
affects the buoyancy of the weights, i.e. the sample to be weighed,
is determined using external climate sensors.
[0004] With respect to mass comparators it is known that the air
buoyancy is determined by a comparison measurement of two reference
objects having a mass and density that are already known
beforehand.
[0005] It is also known that the temperature, the air pressure and
the humidity also affect the balance itself, in particular, the
load cell. For this reason, in order to compensate for the
variations in the balance display with changing ambient parameters,
correction factors are stored in the device, for example, in the
form of curves or tables. In addition, temperature and air humidity
sensors are disposed, in particular, in the area of the load cell.
Then these temperature and air humidity sensors are used to
automatically correct the balance itself, as a function of the
changing ambient conditions, also called climate changes.
[0006] Thus, for example, the German patent DE 37 14 540 C2
describes a method for automatically calibrating a high resolution
electronic balance, wherein such environmental factors as the
temperature change and the humidity change, both of which are
detected from the outside, are used in order to calibrate the
balance itself. The corresponding calibration factor is determined
by a computer and corrects the weighing result.
[0007] The German patent DE 299 12 867 U1 discloses an analytical
balance with a measuring sensor for ambient parameters. In this
case the analytical balance has a display that is provided on the
rear wall of the weighing chamber. The display shows the
temperature in the weighing chamber and the air humidity in the
weighing chamber as well as in general the air pressure that is
usually present. In this case it is assumed that, when the air is
wet, the surface of the sample to be weighed will be covered with
moisture, which is a function of the variances in the air humidity.
Therefore, the operator is informed by the display that, for
example, with changing air humidity, the sample to be weighed
should remain in the weighing chamber longer, in order to obtain a
stable end value of the surface moisture. If there are extreme
fluctuations in the air pressure, then the operator can perform a
so-called buoyancy correction by feeding the displayed data to a
processor in the balance by via of an input unit. With respect to
the temperature, this temperature is used to determine the
deviation from the reference temperature and to consider
corresponding correction factors.
[0008] Finally, there are also climatized measuring chambers, in
which there are precision balances, into which the climate data of
the measuring chamber are entered. The climate data from the
climate module or the sensors thereof are fed manually or
automatically into the balance.
SUMMARY
[0009] An object of the present invention is to provide a mass
comparator that is compact and that ensures an improved measuring
accuracy with less complexity.
[0010] This object, according to one formulation of the invention,
is achieved with a mass comparator, comprising a weighing chamber;
a draft shield, which surrounds the weighing chamber; a climate
module, which includes an air pressure sensor, an air humidity
sensor and an air temperature sensor and which is disposed in the
weighing chamber in such a way that it can be removed; a processor;
a data input unit; and a data transmission path, over which data
can be exchanged between the climate module and the processor. The
object, according to a further formulation, is achieved with a
climate module configured to electrically couple to a mass
comparator in a detachable manner, wherein the climate module forms
a self-contained modular unit and comprises an air pressure sensor,
an air humidity sensor and an air temperature sensor, as well as a
data transmission path, over which data can be sent to a processor
external to the climate module.
[0011] The invention makes use of the idea of combining all of the
components and functions, which are necessary for compensating for
the climate changes in the weighing values, in the mass comparator.
Therefore, no external computers, sensors, etc. are necessary.
Instead, the user can be provided with a compact measurement
laboratory, which can be designed in such a way that it is even
portable. Since the climate module is interchangeable (i.e., can be
detached from the balance without destroying it), it can be sent,
if desired, to an external institute or service provider for
calibration. In the meantime the mass comparator can still be used
by installing a replacement climate module. As a result, it is
possible to have on a rolling basis one or (in the case of several
mass comparators) a plurality of climate modules being calibrated,
while measuring with the other climate modules.
[0012] The climate module offers an additional advantage that older
balances can be retrofitted. The only requirement for such a
retrofitting is, in addition to the data transmission path, the
software of the processor.
[0013] In terms of accuracy the mass comparator of the invention
has the advantage that the climate data are measured behind the
draft shield (and not just in the chamber, in which the balance is
located). Therefore, precisely the air density that is relevant to
the buoyancy is determined. In addition, since the buoyancy values
are transmitted automatically to the processor, transmission errors
can be virtually eliminated. According to the German patent DE 299
12 867 U1, such transmission errors are possible, for example, when
transferring values from the so-called calibration certificate into
the calibration software.
[0014] According to one embodiment, it is provided that the climate
module is connected to the processor via an electrical plug-in
connection. The plug-in connection can be integrated into a
mechanical receptacle, which is used to attach the climate module
to the precision balance. In this way the data transmission path to
the processor is automatically established, when the climate module
is installed inside the draft shield.
[0015] According to an alternative embodiment, it is provided that
the climate module is coupled to the processor over a wireless
transmission. In this case the climate module can be disposed at
any location inside the draft shield, for example, on a partition
wall, where it will interfere the least, without having to take
into consideration whether a plug-in connection can be arranged at
this location in such a way that it is useful. In addition, the
absence of a plug-in connection has the advantageous effect that
the interior of the weighing compartment can be designed to be
smoother and, therefore, easier to clean.
[0016] Preferably the climate module includes an air pressure
sensor, an air humidity sensor and an air temperature sensor. These
sensors can be used to record the climate data that are essential
for a precise measurement.
[0017] In addition, it can be provided that inside of the climate
module there is a sensor for determining the degree of ionization
in the weighing chamber; and this sensor is coupled to the data
transmission path. As a result, an additional parameter can be
determined and taken into account in the correction of the weighing
result. The processor generates, as a function of a certain degree
of ionization, an output signal, for example, to actively change
the degree of ionization, by using an ionization device, which is
activated after reaching certain degrees of ionization.
Furthermore, a display can also indicate to the user that the
degree of ionization inside the weighing chamber is too high and
should be discharged.
[0018] It can also be provided that the climate module has a light
sensor, which is coupled to the processor. Such an arrangement
allows another parameter to be determined and taken into account in
correcting the weighing result. The processor can output an output
signal following a specified level of incident light. As a result,
it is possible to determine the effect of the incident light on the
weighing process, so that appropriate steps can be taken in the
process itself. The output signal can also be an indicator.
[0019] According to one embodiment, it is provided that the
processor is designed such that it uses the air pressure, the air
humidity and the air temperature in the weighing chamber to
determine, based on the density of the sample to be weighed, the
air buoyancy of at least one test sample as well as to determine
the buoyancy correction factor. This arrangement makes it possible
to receive from the climate module the metrologically traceable
values at the same time as the transfer of the mass value, with
which the processor is able to correct the weighing result.
[0020] According to one embodiment, an electronic memory, in
particular, an EEPROM, which can be read out by an external reader
and in which the calibration values and the correction values for
the climate module can be stored, is provided inside the climate
module. In order to make adjustments, the calibration values can be
stored in an electronic memory on the climate module, in
particular, can be stored in an EEPROM. This is done at an external
service provider. If the climate module is then reconnected to the
mass comparator, these data are then immediately available to the
processor of the balance. In addition, the memory can be used to
store, among other things, at least some of the following sensor
calibration data, for example: the number of the calibration
certificate, the current calibration values, the calibration date,
the name of the calibration laboratory, the name of the person in
charge and the calibration history. In addition, so-called
uncertainty values can also be stored for each climate variable in
the memory of the climate module, so that, for example, in order to
compute the air density, the computation of the uncertainty of the
air density can also be performed by the mass comparator.
[0021] According to one embodiment, it is provided that the climate
module can also be used as a stand-alone unit external to a balance
and can be connected to a USB port of a PC via an I.sup.2C bus.
This arrangement makes it easier to perform an external
calibration. In addition, the climate module can be used in other
applications to record climate variables without having to be
connected to a balance. For this purpose the printed circuit board
of the climate module can easily have a plug-in extension, in order
to be connected to a USB adapter.
[0022] Furthermore, the object, according to yet another
formulation of the invention, is achieved with a method for
operating a mass comparator comprising a weighing chamber, which is
separated from the surrounding area by a draft shield and in which
an air pressure sensor, an air humidity sensor and an air
temperature sensor are arranged, wherein the sensors are coupled to
a processor and wherein the sample to be weighed is weighed in the
form of a test sample and at least one reference weight. In this
case it is provided that the air pressure, the air humidity and the
air temperature in the weighing chamber are determined by the
sensors. In addition, the density of the sample to be weighed, the
mass of which sample is to be determined, is entered into the mass
comparator. Furthermore, the air buoyancy of at least the test
sample as well as the buoyancy correction factor are determined
from the air pressure, the air humidity, the air temperature and
the density of the sample to be weighed. Finally the corrected,
conventional weighing value of the test sample is determined.
[0023] The inventive method determines the current air density
during the weighing process from a number of parameters in the
weighing chamber and not only, as proposed in DE 299 12 867 U1,
with the air pressure. The actual current density and the density
of the sample to be weighed are used to determine the air buoyancy
of at least the test sample as well as to determine the buoyancy
correction factor and, thus, the corrected conventional mass.
Except for the density input, all other data items are entered
automatically. That is, neither the temperature, the air humidity,
nor the air pressure is entered manually into the processor; the
data flow electronically via the sensors into the processor.
[0024] It is not absolutely necessary (but is not excluded) that
two different reference weights or reference bodies be used to
determine the density; instead, it is also possible to work with
one reference weight.
[0025] It is also possible to compensate the measured values for
changes inside the load cell due to climate changes.
[0026] The measurement of the corresponding data to determine the
buoyancy in the draft shield has the advantage that precisely the
air density that is relevant to the buoyancy is determined.
[0027] Due to the fact that the buoyancy values are transmitted
automatically to the processor, it is possible to virtually
eliminate transmission errors, which are possible, according to the
German patent DE 299 12 867 U1, in the course of transferring the
values from the so-called calibration certificate into the
calibration software.
[0028] Not only the air buoyancy of the sample to be weighed, the
weight of which is to be determined, but also the air buoyancy of
the reference weight is determined from the air pressure, the air
humidity and the air temperature as well as the density of the
reference weight, in order to determine the mass of the reference
weight, where the mass is corrected by its air buoyancy.
[0029] In addition, it can be provided that the degree of
ionization in the weighing chamber is determined, and that the
processor outputs an output signal, as a function of the degree of
ionization that is determined. It can also be provided that a light
sensor determines the level of incident light in the weighing
chamber; and preferably that the processor outputs an output signal
after a specified level of incident light. With respect to the
advantages, reference is made to the above explanations.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] Additional features and advantages of the invention will
become apparent from the following description and from the
following drawings, to which reference is made. The drawings show
in:
[0031] FIG. 1 an exploded view of a mass comparator, according to
the invention,
[0032] FIG. 2 a perspective view of an inventive climate module,
which can be used in the mass comparator of the invention,
[0033] FIG. 3 a side view of the climate module from FIG. 2 without
the outer housing,
[0034] FIG. 4 a plan view of the climate module from FIG. 2, also
without the outer housing, and
[0035] FIG. 5 a flow chart showing the process of the
invention.
DETAILED DESCRIPTION
[0036] FIG. 1 shows a high resolution electronic mass comparator
that in this exemplary embodiment permits mass comparisons to be
performed for the accuracy classes E1-F2 in compliance with OIML R
111-1.
[0037] The mass comparator comprises a load cell 14 with a base 12,
in which a weighing module 10, which is not shown in more detail,
is housed. In addition, the load cell 14 comprises a weighing
chamber 16, which is formed by a draft shield with adjustable side
walls 18, a front wall 20 and a rear wall 22. The weighing chamber
16 is separated from the surrounding area by the draft shield. A
weighing dish 24 is used to hold the sample to be weighed.
[0038] An electronic evaluation system 26, which is designed as a
separate part in this embodiment, is electronically coupled to the
load cell 14 via a cable 28. A display unit 30, which is coupled to
the evaluation system 26, is used both as a display and as a data
input unit. While the electronic evaluation system 26 and the
display 30 are embodied as components physically separated from the
weighing module 10 in the illustrated embodiment, other embodiments
can incorporate one or both of these components 26 and 30 into the
weighing module 10.
[0039] The electronic evaluation system 26 houses, among other
things, a processor 32, which receives data from the load cell
14.
[0040] The weighing chamber 16 has a climate module 34, which is
designed as a structurally separate unit and which can be
mechanically coupled to the rear wall 22 through a disconnectable
plug-in connection (hence, is attached in a manner allowing the
climate module to be disconnected without destroying it), and, in
particular, preferably without the aid of a tool.
[0041] For this purpose the rear wall 22 has two slots 36, which
are spaced apart from each other and in which flexible locking
hooks 38 (see also FIG. 2) engage with the outer housing 40 of the
climate module.
[0042] FIGS. 2 to 4 show the climate module 34 in more detail.
[0043] The outer housing 40 has a number of apertures 42, through
which the interior of the outer housing 40 changes over into the
weighing chamber 16 and becomes a part of the weighing chamber 16,
so that the climate inside the weighing chamber 16 corresponds to
the climate inside the outer housing 40.
[0044] The climate module 34 is electronically coupled via an
electrical plug-in connection to a corresponding plug receptacle 44
in the rear wall 22. The plug receptacle 44 is electrically
connected to the processor 32. A plug 46 with contacts 48 is
plugged into the plug receptacle 44 on the climate module 34. As a
result, the plug 46 forms a module-sided part of the electrical
plug-in connection.
[0045] As an alternative to an electrical plug-in connection, a
wireless transmission, such as WLAN or Bluetooth, can be used.
[0046] The electrical plug-in connection (or the wireless
transmission used as an alternative) forms a data transmission
path, over which the data can be transferred from the climate
module 34 to the processor 32 and, if desired, can be transferred
back to the climate module.
[0047] The plug 46 is preferably a section of a circuit board 50,
on which a plurality of sensors for detecting the climate in the
weighing chamber 16 are disposed. Therefore, an air temperature
sensor 52, an air humidity sensor 54, a light sensor 56, which is
arranged directly in the vicinity of an aperture 42, and a sensor
58 for detecting the degree of ionization in the weighing chamber
16 are provided on the circuit board 50, and an electronic memory
60 is also provided on the circuit board. An air pressure sensor 62
is mechanically and electrically coupled to the circuit board 50
with a bracket 64.
[0048] A plurality of the sensors can also be combined into
combined sensors.
[0049] A wall 66 closes the shell-like outer housing 40, so that
the narrow tongue-like section of the circuit board 50 that is
located to the right of the wall 66 in FIG. 4, can be inserted into
the rear wall 22 and the plug receptacle 44.
[0050] Each sensor is coupled to the processor 32 via corresponding
contacts 48. Similarly the memory 60 is coupled to the processor
32.
[0051] The mass comparator operates according to the following
method, which is explained with reference to FIG. 5.
[0052] In the steps 100 and 102 the density of the sample to be
weighed (test weight, also called the test sample B, and the
reference weight A) is entered into the mass comparator, for
example, using the display unit 30, which is also used
simultaneously as a data input unit by way of, for example, the
touch screen. As an alternative, the density of the sample to be
weighed can have already been stored.
[0053] A sample to be weighed is placed on the weighing dish 24,
and, in particular, according to the specified process steps, for
example, first the reference weight A, then twice the test sample B
and finally again the reference weight A. These process steps
relate to comparison weighing, which in step 104 results in the
display of the difference of the balance.
[0054] The air pressure, the air humidity and the air temperature
can be determined in step 106 by the sensors 62, 54 and 52,
respectively; and the corresponding data are then transmitted to
the processor 32.
[0055] The air density is determined in the processor 32 (see step
108). The input densities of the reference weight A and the test
sample B are used in the processor to determine the air buoyancy
correction factor in step 110 and/or to determine the air buoyancy
of the sample to be weighed, as a function of the air pressure, the
air humidity, the air temperature as well as the density of the
sample to be weighed; and in step 112 the conventional weighing
result of the test sample B, i.e., the mass of the test sample B
that is corrected by its air buoyancy, is determined and displayed
as a protocol in the display unit 30, where in this case the
conventional mass 114 of the reference weight also enters into the
determination of the conventional mass of the test sample.
[0056] In addition, the calibration values and the correction
values for the climate module 34, which had been input during the
calibration of the climate module 34, are stored in the memory
60.
[0057] This calibration is performed outside of the mass
comparator. To this end the climate module 34 is simply unplugged
from the weighing chamber 16 without having to disconnect a wire
connection. Then the climate module 34 is sent to an appropriate
calibration institute that stores the number of the calibration
certificate, i.e., the new calibration values, the calibration
date, the name of the calibration laboratory, the name of the
person in charge and the calibration history in the memory 60.
These values are read out later by the application program, when
the climate module 34 is once again in the mass comparator, and
flow directly into the computation.
[0058] Even the values of the light sensor 56 and the sensor 58 for
determining the degree of ionization in the weighing chamber 16 are
determined.
[0059] For example, when the level of incident light increases, a
corresponding signal will be shown on the display that, for
example, the measurement is uncertain due to increased exposure to
sunlight and, thus, due to a temperature change in the weighing
chamber. As a result, the processor sends an output signal as a
function of the exposure to incident light.
[0060] As soon as the degree of ionization is too high, an
ionization device is activated; and this ionization device ionizes
the air in the weighing chamber and makes sure that the sample to
be weighed is discharged, or a warning about an excessive charge of
the sample to be weighed is sent.
[0061] The memory 60 is preferably an EEPROM.
[0062] In addition, the connection between the climate module 34
and the rest of the mass comparator is implemented using an
I.sup.2C bus.
[0063] The climate module 34 can be connected to a computer via a
USB adapter, into which the climate module is inserted, in order to
calibrate the sensors 52 to 58 and 62 without having to connect the
climate module 34 to the mass comparator.
[0064] As can be seen, the climate module is designed so that it
can also be used as a stand-alone unit outside a balance and can be
connected to a USB port of a PC using an I.sup.2C bus.
LIST OF REFERENCE NUMERALS AND CHARACTERS
[0065] 10 weighing module [0066] 12 base [0067] 14 load cell [0068]
16 weighing chamber [0069] 18 side wall [0070] 20 front wall [0071]
22 rear wall [0072] 24 weighing dish [0073] 26 evaluation system
[0074] 28 cable [0075] 30 display unit [0076] 32 processor [0077]
34 climate module [0078] 36 slots [0079] 38 locking hooks [0080] 40
outer housing [0081] 42 apertures [0082] 44 plug receptacle [0083]
46 plug [0084] 48 contacts [0085] 50 printed circuit board [0086]
52 air temperature sensor [0087] 54 air humidity sensor [0088] 56
light sensor [0089] 58 sensor [0090] 60 memory [0091] 62 air
pressure sensor [0092] 64 bracket [0093] 66 wall [0094] 100 step
[0095] 102 step [0096] 104 step [0097] 106 step [0098] 108 step
[0099] 110 step [0100] 112 step [0101] 114 conventional mass of the
reference weight [0102] A reference weight [0103] B test sample
* * * * *