Beckhoff EP3356-0022 Documentation page 14

Product overview
The nominal characteristic value 2 mV/V means that, with a supply of U
load cell, the maximum output voltage U
always a nominal value – a manufacturer's test report is included with good load cells stating the
characteristic value determined for the individual load cell, e.g. 2.0782 mV/V.
Minimum calibration value V
This indicates the smallest mass that can be measured without the maximum permissible error of the load
cell being exceeded [RevT].
This value is represented either by the equation V
E (e.g. 0.01).
max
This means that a load cell with E
V = 10 kg / 10000 = 1 g or V
min
Accuracy class according to OIML R60
The accuracy class is indicated by a letter (A, B, C or D) and an additional number, which encodes the scale
interval d with a maximum number n
intervals.
The classes specify a maximum and minimum limit for scale intervals d:
• A: 50,000 – unlimited
• B: 5000 – 100,000
• C: 500 – 10,000
• D: 500 – 1000
The scale interval n = 4000d states that, with a load cell with a resolution of V
max
scales can be built that has a maximum measuring range of 4000d * V
minimum specification, an 8 kg set of scales could be built – if the application allows – with the same load
cell, wherein the calibratable resolution would then fall to 8 kg/4000d = 2 g. From another point of view the
scale interval n is a maximum specification; hence, the above load cell could be used to build a set of
max
scales with a measuring range of 4 kg, but a resolution of only 2000 divisions = 2 g, if this is adequate for the
respective application. Also the classes differ in certain error limits related to non-repeatability/creep/TC
Accuracy class according to PTB
The European accuracy classes are defined in an almost identical way (source: PTB).
Class
|
Fine scales
||
Precision scales
|||
Commercial scales
||||
Coarse scales
Minimum application range or minimum measuring range in % of rated load
This is the minimum measuring range/measuring range interval, which a calibratable load cell/set of scales
must cover.
Example: above load cell E
14
= 10 V * 2 mV/V *E = 20 mV. The nominal characteristic value is
D
min
min
= 10 kg has a maximum resolution of
max
= 10 kg * 0.01 % = 1 g.
min
(*1000); e.g. C4 means Class C with maximally 4000d scale
max
Calibration values
0.001 g <= e
g <= e <=0.05 g
g <= e
g <= e <=2 g
g <= e
5 g <= e
= 10 kg; minimum application range e.g. 40 % E
max
Version: 1.1.0
=10 V and at the full load E
S
= E / n (where n is an integer, e.g. 10000), or in % of
max
= 4 kg. Since V
min
Minimum load
100 e
20 e
50 e
20 e
20 e
10 e
max
= 1 g, a calibratable set of
min
is thereby a
min
Max/e
Minimum Maximum
value value
50000
100 100000
5000 100000
100 10000
500 10000
100 1000
max
EP3356-0022
of the