Festo Кабели и принадлежности - Manual (Page 71)

5. Data structure
5−13
Festo P.BE−SPC200−COM−CANDN−EN en 0511a
5.2.3 Parameter commands
These commands write or read parameters, e.g. position
registers or flags. They require a LOAD DATA handshake.
The handshake cycle for writing data PLC } SPC200
The Command Message is parametrized by the user program.
The transmission cycle begins when the LOAD signal (bit 7 in
byte 0 of the Command Message) is set. The SPC200 accepts
the data, checks them for plausibility and limit values and, if
necessary, generates a fault message. With LOAD COMPLETE
it informs the PLC that data transmission is finished. A transĆ
mission cycle is concluded when the user cancels the LOAD
signal. During the handshake cycle no update data are transĆ
mitted. The following diagram explains the correlation:
To SPC200:
To PLC:
PLC:
SPC200:
1 2 3
1
SPC200 accepts the Command Message
2
SPC200 gives the Response Message
3
If necessary, the SPC200 sends the fault protocol here.