Instruction manual
Page 9
TE67X000002150 Ethernet Module
Status and weight transfer using EtherNetIP
IM-TE91K013-EN2
4) Data Processing
4.1 Zeroing, calibration and weight calculation
Calculation of system weight(s) is done by addition of the weight registers for the load cells belonging to
the system. This is explained below.
Note
that the result is only valid if all status registers for the load
cells in question indicate no errors. It should also be noted that it is up to the master to ensure the
usage of consistent load cell data when calculating the system weight (the used data should come from
the same telegram).
4.1.1 Zeroing of weighing system
Zeroing of a weighing system (all load cells in the specific system) should be performed as follows,
taking into account that no load cell errors may be pre-sent during the zeroing procedure:
1) The weighing arrangement should be empty and clean.
2) The EtherNetIP master verifies that no load cell errors are present, after which it reads and
stores the actual weight signals for the load cells of the actual system in corresponding zeroing
registers:
LcZero[x]=LcSignal[x]
3) After this the uncalibrated gross weight for load cell X can be calculated as:
LcGross[
X
] = LcSignal[
X
] – LcZero[
X
]
4.2 Corner calibration of weighing system
In systems where the load is not always placed symmetrically the same place (for example a platform
weight where the load can be placed randomly on the platform when a weighing is to take place), a fine
calibration of a systems corners can be made, so that the weight indicates the same independent of the
position of the load. This is done as follows:
1)
Check that the weighing arrangement is empty. Zero the weighing system.
2)
Place a known load (CalLoad) directly above the load cell that is to be corner calibrated.
3)
Calculate the corner calibration factor that should be multiplied on the uncalibrated gross
weight of the load cell in order to achieve correct showing as:
CornerCalFactor[x] = (CalLoad)/(LcGross[x])
After this the determined corner calibration factor is used to calculate the calibrated gross weight of the
load cell as follows:
LcGrossCal[x] = CornerCalFactor[x] * LcGross[x]
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