
B-63322EN-1/01 6. PROTOCOL B
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(Fig. B)
(1) The remote buffer transmits the DC2 code.
(2) The remote buffer starts transmitting punch-out data.
(3) If data processing in the host computer cannot keep pace with
the rate of data transmission from the remote buffer:
(a) Turning off the CS signal for the remote buffer causes the
remote buffer to stop data transmission after transmitting a
maximum of most two characters, including the character
currently being transmitted. (See Fig. A.)
(b) Transmitting a DC3 code to the remote buffer causes the
remote buffer to stop data transmission, such that the
amount of data transmitted after transmission of the DC3
code does not exceed the overrun. (See Fig. B.)
NOTE
If the RBETX bit of parameter No. 5000 is set to 1,
method (a) cannot be used because, while the CS signal
is off, a SYN/NAK or DC4 code is not transmitted even if
CNC reset or a CNC alarm occurs. In such a cause, use
method (b).
(4) For method (a) in step (3)
Once data processing by the host computer terminates, turning
on the CS signal for the remote buffer causes the remote buffer
to restart data transmission, picking up from the data
immediately after that transmitted last.
For method (b) in step (3)
Transmitting a DC1 code to the remote buffer causes the remote
buffer to restart data transmission.
(5) When the CNC has been reset or an alarm has been issued in the
CNC, the remote buffer transmits, to the host computer, a DC4
code, followed by a SYN code (for reset) or NAK code (for an
alarm).
ON
SYN or
NAK
DC2
ER (output)
RS (output)
SD (output)
DR (input)
CS (input)
DC3 DC1
RD (input)
ON
Reset or alarm
DC4
(5)
(4)(3)
(2)(1)