Beckhoff EP3356-0022 Documentation page 73

• The "Dynamic filter change time" object (0x8000:13) [} 104] is used to set the time interval at which the
existing signal is re-evaluated.
• Object 0x8000:14 [} 104] is used to specify the maximum deviation that is permissible during this time
without filter switching occurring.
Example:
The dynamic filter is to be adjusted in such a manner that a maximum slope of 0.5 digits per 100 ms (5 digits
per second) is possible without the filter being opened. This results in a "calm" measured value. In the case
of a faster change, however, it should be possible to immediately follow the load.
• Dynamic filter change time (0x8000:13) [} 104] = 10 (equivalent to 100 ms)
• Object 0x8000:14 [} 104] is used to specify the maximum deviation that is permissible during this time
without filter switching occurring.
The measured value curve is shown below for a slower (left) and faster (right) change.
Fig. 69: Effect of dynamic IIR filters
• Left: The scales are slowly loaded. The change in the weight (delta/time) remains below the mark of
0.5 digits per 100 ms. The filter therefore remains unchanged at the strongest level (IIR8), resulting in a
low-fluctuation measured value.
• Right: The scales are suddenly loaded. The change in the weight immediately exceeds the limit value
of 0.5 digits per 100 ms. The filter is opened every 100 ms by one level (IIR8 --> IIR7 --> IIR6 etc.) and
the display value immediately follows the jump. After the removal of the weight the signal quickly falls
again. If the change in the weight is less than 0.5 digit per 100 ms, the filter is set one level stronger
every 100 ms until IIR8 is reached. The green line is intended to clarify the decreasing "noise level"
Calculating the weight
Each measurement of the analog inputs is followed by the calculation of the resulting weight or the resulting
force, which is made up of the ratio of the measuring signal to the reference signal and of several
calibrations.
Y = (U / U ) x A
R Diff ref i
Y = ( (Y – C ) / (C – C
L R ZB n
Y = Y * A
S L S
Y = Y * (G / 9.80665)
G S
Y = Y x Gain - Tara
AUS G
EP3356-0022
(1.0) Calculation of the raw value in mV/V
) ) * E (1.1) Calculation of the weight
ZB max
(1.2) Scaling factor (e.g. factor 1000 for rescaling from
(1.3) Influence of acceleration of gravity
(1.4) Gain and Tare
Version: 1.1.0
kg to g)
Commissioning/Configuration
73