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156
Setup Area Allocations
Section 5-2
Also, if the external device is connected using 2-wire connections from an RS-
422A/485 port, send and receive data cannot both be on the same transmis-
sion line at the same time. This will create an additional lag time, t2, or 150
µ
s.
If responses are being received quickly from the external device, i.e., faster
than t1 +t2, create a send delay at the external device or take other measures
to allow for the lag times.
Time Lag t1
With full-duplex mode, the reception buffer is cleared immediately before the
sequence is executed. While both the SEND&RECV commands are being
executed, data is input into the reception buffer and is used as the macro
data.
Note
1.
With full-duplex, RS-232C or RS-422A/485 (1:1 and 4-wire connections)
can be used. RS-422A/485 1:N or 2-wire transmissions cannot be used.
2.
The FLUSH command is used to clear the reception buffer, and can be
used at any time.
3.
Although the received data is discarded until completion of SEND execu-
tion, it is reflected in the character trace.
Baud rate (bps)
Time lag (
µ
s)
1,200
1,116
2,400
578
4,800
288
9,600
144
19,200
73
38,400
36
57,600
24
SEND
operation
Data send
processing
Data cannot be received
during this time.
Rapid
response
Data
reception
Reception buffer cleared
t1 t2 = 150
µ
s
Time lags (see following table)
Transmission
mode
Time reception
buffer cleared
Data reception Character trace
Timing chart (example)
Half-duplex Immediately
before
communications
sequence execution
and immediately
following SEND
completion by the
SEND or
SEND&RECV
command
From SEND
completion to
RECV
completion, or
following SEND
completion to
immediately
before SEND
execution
All during trace
execution
Full-duplex
(See note 1)
Immediately before
communications
sequence execution
(See note 2)
All during
communications
sequence
execution
All during trace
execution
Communications
sequence
Reception buffer
cleared
Data reception
Character trace
RECV
SEND
RECV
(See note 3.)
Communications
sequence
Reception buffer
cleared
Data reception
Character trace
RECV
SEND
RECV
Summary of Contents for SYSMAC CJ1W-SCU21-V1
Page 3: ...iv...
Page 5: ...vi...
Page 9: ...x...
Page 15: ...xvi...
Page 89: ...60 Basic Operating Procedure Section 1 9...
Page 151: ...122 RS 232C and RS 422A 485 Wiring Section 3 4...
Page 173: ...144 Host Link Function for Replacing Existing PLCs Section 4 6...
Page 223: ...194 Enhanced Protocol Macro Functions Section 5 6...
Page 277: ...248 Communications Frames Section 6 8...
Page 291: ...262 Basic Operating Procedure in No protocol Mode Section 7 4...
Page 301: ...272 Auxiliary Area and CIO Area Allocations Section 8 3...
Page 391: ...362 Introduction Appendix A...
Page 421: ...392 CompoWay F Master Protocol Appendix B...
Page 513: ...484 E5 K Digital Controller Read Protocol Appendix F...
Page 571: ...542 E5ZE Temperature Controller Write Protocol Appendix I...
Page 587: ...558 E5 J Temperature Controller Protocol Appendix J...
Page 627: ...598 ES100 Digital Controller Protocol Appendix K...
Page 661: ...632 V500 V520 Bar Code Reader Protocol Appendix M...
Page 697: ...668 3Z4L Laser Micrometer Protocol Appendix N...
Page 717: ...688 Visual Inspection System Protocol Appendix O...
Page 755: ...726 V600 V620 ID Controller Protocol Appendix P...
Page 763: ...734 Hayes Modem AT Command Protocol Appendix Q...
Page 767: ...738 Changing Communications Port Settings Using STUP 237 Appendix R...
Page 781: ...752 Revision History...