Lika H 58 Series, Руководство пользователя

Страница: 53 / 70

Hx58x EtherCAT®
5.1.4 Line Termination
EtherCAT network needs no line termination because the line is terminated
automatically; in fact every slave is able to detect the presence of downstream
slaves.
An EtherCAT slave is able to detect the presence of the signal in the outgoing
line (Port 0) or in the return line (Port 1).
If the slave is not able to detect the signal in its return line then it closes the
communication ring by short-circuiting the TX signal of its outgoing line with
the RX signal of its return line; in this way a telegram received through the
outgoing line is processed and sent back through the TX of the return line.
The slave sends a “carrier signal” or a telegram on TX of the outgoing line
continuously and, once the next slave is connected again, a signal on RX of the
return line is detected again; so the short circuit is removed and the telegrams
are sent on TX of the outgoing line.
5.1.5 Addressing
It is not necessary to assign a physical address to the device (for instance using
a dip-switch) because the addressing of the slave is automatic at power on
during the initial scanning of hardware configuration.
The field for addressing is 32 bits long; there are three kinds of addressing:
•
Auto Increment Addressing = Position Addressing: 16 bits indicates the
physical position of the slave inside the network while 16 bits are scheduled
for local memory addressing; when the slave receives the frame then it
increments the position address and the slave receiving address 0 is the
addressed device;
•
Fixed Addressing = 16 bits indicates the physical address of the slave inside
the network while 16 bits are scheduled for addressing the local memory;
MAN HM58x EC I_E 1.2.odt 53 www.lika.it
www.lika.biz