Panasonic MADHT1105, Руководство по эксплуатации

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7-32
Transmission Sequence
• Transmission protocol
• In case of RS232
• In case of RS485
• Line control
Decides the direction of transmission and solves the contention.
Reception mode... From when the module (host or driver) returns EOT after receiving ENQ.
Transmission mode... From when the module (host or driver) receives EOT after trans-
mitting ENQ.
At contention of transmission and reception... Slave side will enter to reception mode
when it receives ENQ while waiting for EOT after transmitting ENQ, by giving priority
to ENQ (of master side).
• Transmission control
On entering to transmission mode, the module transmits the command block continu-
ously and then waits for ACK reception. Transmission completes at reception of ACK..
ACK may not be returned at transmission failure of command byte counts. If no ACK
is received within T2 period, or other code than NAK or ACK is received, sequence will
be retried. Retry will start from ENQ.
• Reception control
On entering to reception mode, the module receives the transmitted block continuous-
ly. It will receive the command byte counts from the first byte, and continuously receive
extra 3 bytes. It will return ACK when the received data sum becomes 0, by taking this
status as normal. In case of a check sum error or a timeout between characters, it will
return NAK.
Host MINAS-A5
Receiving
data
Transmitting
data
1) ENQ(05h)
2) EOT(04h)
3) Data block
4) ACK(06h)
(or NAK (15h))
5) ENQ(05h)
6) EOT(04h)
7) Data block
8) ACK(06h)
(or NAK (15h))
Receiving
data
Transmitting
data
Host
Module ID : 0 Module ID : 1 1) 81h, ENQ (05h)
2) 81h, EOT (04h)
3) Data block
4) ACK (06h)
(or NAK (15h))
5) 80h, ENQ (05h)
6) 80h, EOT (04h)
7) Data block
8) ACK (06h)
(or NAK (15h))
MINAS-A5
4. Communication
Specifications