Beckhoff EtherCAT EL6001, Документация

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Commissioning
EL600x, EL602x 126 Version: 4.6
The following CoE settings are possible from object 0x8000 and are shown below in their default settings:
Fig. 146: “CoE - Online, EL60x4 terminals” tab
Transfer rates
The terminal has a process image of 22 bytes of user data. It possible to transmit or receive these 22 bytes
every second cycle at the most.
The data is transferred from the terminal to the controller in the first cycle. In the second cycle, the controller
must acknowledge that it has accepted the data.
Therefore, if the cycle time is 10 ms, 50 times 22 bytes can be transmitted per second.
With a set data frame of 8N1, each transmitted byte consists of a start bit, eight data bits and a stop bit. This
is equivalent to 10 bits per user byte.
With the above mentioned settings, a continuous data transfer rate of:
• 50[1/s]*22[Byte]*10[Bit] = 11000 bps
can be achieved.
The next lower baud rate is 9600 baud. Accordingly, continuous transfer at a maximum baud rate of 9600
can be secured with a cycle time of 10 ms.
From firmware 11 the CoE 0x8000:1B supports with explicitBaudrate all baud rates 1000…115200 baud.
When the baud rate is selected, the compatibility of the remote station to the set baud rate must be taken
into account.
If only low quantities of data are to be transmitted or received sporadically (e.g. bar code scanner) the baud
rate can also be set higher, or the cycle time can be enlarged.
If the controller cannot fetch the data quickly enough from the terminal, the data will be stored intermediately
in the internal buffer of the terminal. The buffer for received data has a size of 864 bytes. If this is exhausted,
all further data will be lost.
Another scenario: the controller transfers significantly more data to the terminal than the latter can transmit.
For a ‘baud rate’ setting of 300 and a ‘data frame’ setting of 8N1, the terminal can only transmit 30 bytes per
second. However, if more than these 30 bytes per second are received, a 128 byte transmit buffer will be
written to first in this case also. Once this is full, all further data will be lost.