4BWEIGHING FUNCTIONS
Name Model Length Default Range of values/Meaning
Zero set value
WORD 2 0 Zero set value (digital value)[ 0 to: 2
16
-1]
Char. value/Filter/Other
WORD 2 41 Char. value range LC / Filter setting / Setting data
Adjustment digit 0
WORD 2 0 Scale adjustment zero (AD0) [ 0 to: 2
16
]
Description: see Chapter 5.2.3
Adjustment digit 1
WORD 2 0 Adjustment digits for adjustment weight 1 (AD1) [ 0 to: 2
16
]
Description: see Chapter 5.2.3
Adjustment weight
INT 2 10000 Adjustment weight 1 (AW1)
Description: see Chapter 5.2.3
Table 5-1 Allocation of DR3 for channel 1 / DR4 for channel 2
5.2.1 DR3/4 - Zero set value
After the adjustment the zero set value corresponds to the value for adjustment
digits 0. If the scale is set to zero after the adjustment for correction purposes, the
zero set digits are recalculated; the characteristics of the scale will not be changed
as a consequence, merely shifted.
By means of a parameter bit it can be specified whether the new zero set value will
be saved only in the RAM or also in the EEPROM. If the command "Set to zero" is
used frequently, then the zero set value should only be saved in the RAM memory,
since the maximum number of write cycles of an EEPROMS is limited to 100,000.
When transferring DR3 or DR4 with a pre-assigned zero set value, the saving
always occurs in the EEPROM memory.
5.2.2 DR3/4 – Characteristic value range LC, low-pass filter, mean value filter, setting
data
Dependent on the characteristic value of the connected load cells, the value 1
mV/V, 2mV/V or 4 mV/V must be selected. Since SIWAREX U supplies the load
cells with approx. 6 V, the measurement input is adjusted according to the
anticipated measured voltage (max. 6 mV, max. 12 mV or max. 24 mV). If the
characteristic value of the connected load cells is, for example, 2.85 mV/V, then
the next highest characteristic value must generally be set, i.e. 4 mV/V.
For the suppression of interference, a critically damped low-pass filter of the fourth order
is planned. The following diagram shows the step response of the filter (fg = 2 Hz).
A decimal place can be specified for the Siebert remote display connected. Since
the decimal place cannot be represented in the framework of the 16-bit number
representation, all weight input counts as having this decimal place. For example, if
the decimal place is set to 2, then the measurement range of 20 kg is to be
specified as 2000. As process value the weight value is simultaneously output as
2000 at the SIMATIC port.
SIWAREX U 5-27
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