FIBRO 2480.00.91.40, Руководство по эксплуатации, Страница: 26 / 40

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Operating instructions EtherCatWPM Gateway Fieldbus
Operation
6.3.3.2 EtherCAT multiplexing selection of WPM data holders and WPM pres-
sure sensors
A fieldbus is used to quickly transfer dynamic process data.
To maintain the real-time capabilities during short transfer cycles, only the real-time data that are
absolutely necessary should be transferred.
In the WPM system, the information of the selected pressing tool to be monitored are considered
“necessary data”.
If there are several pressing tools in the reception range, they are locally kept in a list in the WPM
Gateway so they can be called up.
The number of tools in the list is transferred in the EtherCAT process map. The EtherCAT Master
uses a type of addressing procedure (multiplexing) to tell the WPM Gateway which element
(number) from the list is required next.
The same multiplex procedure is also used for selecting WPM pressure sensors in the tool mon-
itored.
If the PLC programme is used to monitor a WPM pressure sensor other than the current one,
its desired number is transferred from the list to the WPM Gateway. The WPM Gateway sends
the desired information to the EtherCAT Master as a response.
This way, the EtherCAT Master cyclically collects all the data and creates its own local list in the
PLC, which can then be easily visualised as needed. If pressing tools are removed from the list
in the WPM Gateway (no reception), the list is reconstructed by the
WPM Gateway. The local copy is adapted by cyclically addressing and reading out the list via
the PLC.
Filters and forms of sorting are used for the local list in the PLC.
6.3.3.3 Reading the data of a WPM pressure sensor
The number of the WPM pressure sensors assigned to the
WPM data holder is displayed in ‘Sensors’ (TxPDO2).
So the data of one of these WPM pressure sensors can be read, the index of the
WPM pressure sensor is written in ‘Active Sensor’ (RxPDO1). If a valid index was specified, the
Gateway acknowledges the index in ‘Active Sensor’ (TxPDO1). The data of the selected sensor
can now be read in ‘Sensor Data’ (TxPDO3).
If the number of sensors is 5, a value of 1 to 5 can be specified as the index.
6.3.3.4 Reading the data of a WPM data holder
In ‘Number of Tools’ (TXPDO1), the number of detected WPM data holders is displayed.
The index of the WPM data holder is written in ‘Active Sensor’ (RXPDO1) so the data of one of
these WPM pressure sensors can be read. If a valid index was specified, the WPM Gateway
acknowledges the index in ‘Active Tool’ (TXPD01). The data of the selected WPM data holder
can now be read in ‘Tool Data’ (TXPDO2).
If the number of detected data holders is 5, a value of 1 to 5 can be specified as the index.