Panasonic MINAS E-series - Manual (Page 164)

164
Communications
State Transition Diagram
RS232C Communications
Idling
Receiving module
Transmitting Module
Waiting for EOT
Transmission of block
Waiting for ACK/NAK
Receiving
Remaining blocks
Waiting for the number
of command bytes
There are requests
for transmission
(within the number
of retries).
ENQ transmission
and T2 start.
There are requests for
transmission but the number of
retries is exceeded.
The number of retries is to be
reset once. A request for
transmission is cleared.
EOT is received.
Size Number of command
bytes + 3
T2 stop
One character is received.
Size Number of command
bytes - 1
ENQ is received and in slave
mode.
ENQ is returned to receiving
buffer (To reception
processing)
NAK is received or T2
times out.
The number of retries is
counted once.
T2 STOP
Transmission buffer is
cleared.
T2 timeout
The number of retries
is counted once.
T2 stop
Transmission buffer is
cleared.
Reception is successful
(checksum is OK when size
becomes 0).
ACK is transmitted.
T1 stop
T1 times out or checksum
error occurs when size
becomes 0.
NAK is transmitted.
T1 stop
One character is received.
Size Number of command bytes -1
Sum Sum + received characters
T1 start
T2 timeout
NAK is transmitted.
T2 stop
ENQ
EOT is
transmitted.
T2 start
ACK is received.
The number of retries
is reset.
T2 stop
The request for
transmission is cleared.
Size becomes zero.
T2 START
The number of command bytes is
received.
Size Number of command bytes +3
Sum Number of command bytes
T1 start, T2 stop