
B-63943EN/02 5.CONNECTION TO CNC PERIPHERALS
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Transmission Method of RS-232-C interface
- Start-stop
Generally, two transmission methods are available at the serial
interface. This CNC use the start-stop method.
With this method, start and stop signals are output before and after
each data bit.
One character in start-stop
b1 b2 b3 b4 b5 b6 b7 b8
Start bit
Data bit
(8 bit including one parity bit)
Stop bits
(2 bits)
- Codes
Transmission codes are as follows:
(i) EIA code and Control codes DC1 to DC4.
(ii) ISO code and Control codes DC1 to DC4 (Optional ISO code
input is necessary.)
The connected external device must be able to recognize the following
control codes, sent from NC.
Control code 8765 4 321
DC1 Tape reader start
○
○
○
DC2 Tape punch
designation
○
○
○
DC3 Tape reader stop
○
○
○
○ ○
DC4 Tape punch release
○
○
○
NOTE
The listed control codes are used for both EIA and
ISO.
In this interface, control codes DC1 to DC4 are used.
(a) NC can control external device by issuing codes DC1 to DC4.
(b) When external processing falls behind the pace of the NC signals
(When NC issues data)
(i) External device can temporarily stop NC data output by
using the NC's CS signal. Data output stops within two
characters including a currently transmitting character when
CS OFF signal is input to NC. When CS signal is turned on
again, data transmission start.
(ii) If control code DC3 is input to NC, NC stops data output
within ten characters. When control code DC1 is input to
NC, NC starts sending data again.
(c) When the external device is equipped with an ISO/EIA converter,
the external device must satisfy the specification shown in Table
5.3.4.