Balluff BVS ID-M1280-F1 Series, Configuration Manual

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BVS ID-M1280xF1-xx-xxx
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4.3.3 Toggle mechanism
If more data is to be transferred with a command or with a response than the cyclical memory area can hold, a
toggle mechanism within the handshake is being used. For this purpose, two additional bits, TI (Toggle-In) and
TO (Toggle-Out) are used in the cyclical memory.
Process input toggle
The PLC has to set the TI bit to 0. After the handshake, the PLC has to set the TI bit to 0 again.
The BVS ID sets the TO bit to 0 at the end of the handshake.
The PLC sets command ID, data length and the first part of the data in the output buffer. The data length
is the length of the entire data to be transferred. Afterwards, the PLC sets the
Job bit.
BVS ID reads the Job bit and then command ID, data length and (partial) data. Based on the data length
and size of the cyclical buffer, BVS ID recognizes that additional data still have to be transferred.
BVS ID sets the Job Start bit, inverts the TO bit and waits for the inverted TI bit.
The PLC reads the inverted TO bit, places the next partial data in the output buffer and then inverts the TI
bit.
BVS ID reads the inverted TI bit and accepts the next partial data. If additional partial data must be
transferred, continue with 3, otherwise with 6.
BVS ID accepts the command and executes it and sets command status, data length and (partial) data
in the input buffer and then the Job End bit.
The PLC reads the Job End bit and then command status, data length and (partial) data.
The PLC resets the Job bit and the TI bit if necessary.
BVS ID reads the reset Job bit, withdraws the Job End bit, the Job Start bit, and the TO bit if necessary
and is ready for the next command.
Please note the double bit string chapter in Process Data Buffer .
NOTE
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