Beckhoff ELX3351, Руководство по эксплуатации

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Parameterization and programming
ELX3351 44 Version: 1.3.1
5.3.3 Taring
When taring, the scales are zeroed using an arbitrary applied load; i.e. an offset correction is performed. This
is necessary for the gross/net compensation of goods that cannot be weighed without a container that has a
mass of its own.
The ELX3351 supports 2 tarings; it is recommended to set a strong filter when taring.
• Temporary tare
The correction value is NOT stored in the terminal and is lost in the event of a power failure.
To this end the command 0x0001 is executed on CoE object 0xFB00:01 (binary dialog in the System
Manager: 01 00). This sets the tare object (
0x8000:22 [ } 60] ) such that the display value is 0.
Note: in the case of a device restart (INIT->OP) the tare is not deleted.
In addition this tare can be executed via the control word:
Fig. 36: Control word, tare
• Permanent tare
The correction value is stored locally in the terminal's EEPROM and is not lost in the event of a power
failure.
To this end the command 0x0002 is executed on CoE object 0xFB00:01 (binary dialog in the System
Manager: 02 00). This sets the tare object (
0x8000:22 [ } 60] ) such that the display value is 0.
Note
Local storage
The values modified during the theoretical and practical calibration are stored in a local
EEPROM. This can be written to up to 1 million time. In order to prolong the life of the EEP-
ROM, therefore, the commands should not be executed cyclically.
5.3.4 Overview of commands
The functions described above are carried out by means of commands in the standardized object 0xFB00.
Index Name Comment
FB00:01 Request Entry of the command to be executed
FB00:02 Status Status of the command currently being executed
0: Command executed without error.
255: Command is being executed
FB00:03 Response Optional response value of the command
The function blocks FB_EcCoESdoWrite and FB_EcCoESdoRead from the TcEtherCAT.lib (contained in the
standard TwinCAT installation) can be used in order to execute the commands from the PLC.
Commands of the ELX3351
The following commands can be transferred to the terminal via the CoE entry 0xFB00:01.
Command Comment
0x0101 Execute zero balance
0x0102 Execute calibration
0x0001 Execute tare procedure (value is NOT saved in the terminal's EEprom)
0x0002 Execute tare procedure (value is saved in the terminal's EEprom)