Understanding the Communication Protocols
D–3
DF1 Full-Duplex Protocol
DF1 Full-Duplex communication protocol combines data transparency (ANSI —
American National Standards Institute — specification subcategory D1) and 2-way
simultaneous transmission with embedded responses (subcategory F1).
The MicroLogix 1000 controllers support the DF1 Full-Duplex protocol via RS-232
connection to external devices, such as computers, the Hand-Held Programmer
(catalog number 1761-HHP-B30), or other MicroLogix 1000 controllers. (For
information on connecting to the Hand-Held Programmer
, see its user manual,
publication 1761-6.2).
DF1 Full-Duplex Operation
DF1 Full-Duplex protocol (also referred t
o a
s D
F1 point-to-point protocol) i
s u
seful
wher
e R
S-232 point-to-poin
t c
ommunication i
s r
equired. Thi
s t
yp
e o
f protoco
l s
upports
simultaneou
s t
ransmission
s b
etween two device
s i
n both directions. DF1 protocol
control
s m
essage flow, detect
s a
n
d s
ignal
s e
rrors
, a
nd retrie
s i
f error
s a
r
e d
etected.
DF1 Full-Duplex Configuration Parameters
When the system mode driver is DF1 Full-Duplex, the following parameters can be
changed:
Parameter Options Default
Baud Rate
Toggles between the communication rate of 300, 600, 1200, 2400, 4800
➀
,
9600, 19200, and 38400
➀
.
9600
➁
Node Address
Valid range is 0–254 decimal for MicroLogix 1000 Series C and later
discrete and all MicroLogix 1000 analog. Not configurable for MicroLogix
1000 Series A and B discrete.
1
Parity None No Parity
Stop Bits None 1
Error Detection None CRC
DLE NAK retries None
N retries
③
DLE ENQ retries None
N retries
③
ACK Timeout None 1 s
Duplicate Packet Detection None Enabled
Control Line None No Handshaking
Embedded Responses None Enabled
➀
Applicable only to MicroLogix 1000 Series D or later discrete and all MicroLogix 1000 analog controllers.
➁
I
f r
etentive communicatio
n d
ata is lost
, d
efault is 120
0 f
o
r M
icroLogix 100
0 S
eries A
, B
, o
r C d
iscret
e o
nly. Fo
r M
icroLogix 1000
Serie
s D or l
ate
r d
iscret
e a
n
d a
ll MicroLogix 100
0 a
nalog, i
f r
etentive communicatio
n d
ata is lost
, b
au
d r
at
e d
efaults t
o 9
600.
➂
N=255 for MicroLogix 1000 Series A and B discrete. N=6 for MicroLogix 1000 Series C and later discrete and all MicroLogix
1000 analog.
efesotomasyon.com - Allen Bradley,Rockwell,plc,servo,drive
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