Allen-Bradley 1785-KE User manual

!"#$%&'()'*
!"#$%&'()*+*
,-./0*1(2345
678849-:*+-79
;9+<=>*:<
?7@43<
A6*+B(C7B(!"#$%&'D
E33<9FG=*@3<1

!"#$%&'(#"&)*$+*, &&-.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&
!"#$%&' ()*+&,%-.&/ ((01(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
23'$4/&(45(6"-/(7#83#9 ((0
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
:"4(;"439<(=&#<(6"-/(7#83#9 ((0
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
;&'-&/(>(?8"#8,&@&8%/ ((A
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
B'&C3&8%9D(E/&<(6&'@/ ((A
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
2'&,#3%-48#'D(F4%&/ ((G
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
=&9#%&<(2'4<3,%/ ((G
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
=&9#%&<
($3*9-,#%-48/ ((H1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
/0120#13&45&6(1&789:;<=&*$>&?*6*&@#%(3*A&B,+" &&7.&.&.&.&.&.&.&.&
!"#$%&' ()*+&,%-.&/ ((I1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
:"#%(-/(%"&(IJKHLM?(74<39&N ((I
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
:"#%(-/(O#%#(P-Q"R#D(293/N ((0
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
6"&(2"D/-,#9(S-8T(S#D&' ((A
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
O&9-.&'D()'<&'(45(!4@@#8</ ((J
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
U$$9-,#%-48/ ((K
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
C$"6*,,#$%&6(1&789:;<= &&7.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&
!"#$%&' ()*+&,%-.&/ ((I1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
;&%%-8Q
(%"&(!4@@38-,#%-48()$%-48(;R-%,"&/ ((I1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
;R-%,"(U//&@*9D(;:LIV(=;L0A0L!(S-8T(B&#%3'&/ ((A
1(1(1(1(1(1(1(1(1(1(1(1(1(
;R-%,"(U//&@*9D(;:L0V(O#%#(P-Q"R#D(293/(F4<&(U<<'&// ((H
1(1(1(1(1(1(
;R-%,"(U//&@*9D(;:LAV(!4@@38-,#%-48(=#%&/(#8<(
S4,#9W=&@4%&()$%-48 ((K1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
;R-%,"(U//&@*9D(;:LG ((X
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
7438%-8Q(%"&(IJKHLM?(74<39& ((IY
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
7#T-8Q(!488&,%-48/(%4(%"&(IJKHLM? ((II
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
24R&'-8Q(E$(%"&(IJKHLM?(74<39& ((IA
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
D4$$1E6#$% &F 4+2&GH;-I-;D&?10#E1&64&6(1&789:;<= &&7.&.&.&.&.&.&.&
!"#$%&' ()*+&,%-.&/ ((I1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
6"&(=;L0A0L!(2)=6(!488&,%4' ((I
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
?9&,%'-,#9(!"#'#,%&'-/%-,/(45(%"&(=;L0A0L!(24'% ((0
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
!"#'#,%&'(6'#8/@-//-48 ((0
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
!#*9-8Q(54'(Z43'(=;L0A0L!(O&.-,& ((A
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
O-'&,%(!488&,%-48(%4(#(!4@$3%&' ((H
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
!488&,%-48(%4(U84%"&'(!4@@38-,#%-48(74<39& (([
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
!488&,%-48(%4(#(74<&@ ((K
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
!"44/-8Q(#(74<&@(54'(24-8%L%4L24-8%WB399LO3$9&\(U$$9-,#%-48/ ((X
1(1(1(1(
E/-8Q(%"&(IJKHLM?(-8(#8(U3%4LU8/R&'(U$$9-,#%-48 ((II
1(1(1(1(1(1(1(1(1(1(1(1(1(
Table of Contents

Table of Contents##
!"44/-8Q (#(74<&@(54'(739%-<'4$WP#95LO3$9&\(U$$9-,#%-48/ ((I01(1(1(1(1(1(1(
D4JJ+$#E*6#$%&'(24+%(&6(1&789:;<=&)4>+,1 &&7.&.&.&.&.&.&.&.&.&.&
!"#$%&' ()*+&,%-.&/ ((I1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
U$$9-,#%-48(IV(!488&,%-8Q(#(!4@$3%&'(%4(O#%#(P-Q"R#D(293/ ((I
1(1(1(1(1(
!4@$3%&'(%4(2S!LH ((0
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
2S!L0(F4'@#9(E8$'4%&,%&<(:'-%& ((A
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
2S!L0(F4'@#9(E8$'4%&,%&<(=&#< ((G
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
2S!LA(F4'@#9(E8$'4%&,%&<(:'-%&(]:4'<(=#8Q&(:'-%&^ ((H
1(1(1(1(1(1(1(1(
2S!LA(F4'@#9(E8$'4%&,%&<(=&#<(]:4'<(=#8Q&(=&#<^ (([
1(1(1(1(1(1(1(
U$$9-,#%-48
(0V
!4@@38-,#%-8Q(>&%R&&8(6 R4(O#%#(P-Q"R#D(293/(F&%R4'T/ ((J1(1(1(
2S!LH(:'-%&(!4@@#8</ ((K
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
2S!LH(=&#<(!4@@#8</ ((X
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
2'4Q'#@(_&'-5-,#%-48 ((IY
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
U$$9-,#%-48(AV(739%-<'4$(U$$9-,#%-48/(:-%"(%"&(IJKH`M?(;&'-&/(> ((II
1(1(
?\#@$9&
(IV(7#/%&'(%4(;9#.&(!4@@38-,#%-48 ((IA1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
?\#@$9&
(0V(;9#.&(%4(7#/%&'(!4@@38-,#%-48 ((I[1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
2S!L0(E8$'4%&,%&<(:'-%& ((I[
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
2S!L0(E8$'4%&,%&<(=&#< ((IJ
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
2'4Q'#@(_&'-5-,#%-48 ((IK
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
?\#@$9&
(AV(;9#.&(%4(;9#.&(!4@@38-,#%-48 ((IK1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
2S!L0(E8$'4%&,%&<(:'-%& ((IX
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
=&#<(!4@@#8< ((0Y
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
2'4Q'#@(_&'-5-,#%-48 ((0I
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
2499-8Q(74'&(6"#8()8&(2S!LH(48(#(O#%#(P-Q"R#D(293/ ((0I
1(1(1(1(1(1(1(
E/-8Q
(%"&(739%-<'4$(?\$#8/-48(O-Q-% ((001(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
789:;<=&?#*%$4"6#E&'44," &&7.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&
!"#$%&' ()*+&,%-.&/ ((I1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
E/-8Q(%"&(S?O(a8<-,#%4'/ ((I
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
6"&(IJKHLM?(O-#Q84/%-,(!438%&'/ ((A
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
:"#%(-/(#(O-#Q84/%-,(!438%&'N ((A
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
P4R(%4(=&#<(O-#Q84/%-,(!438%&'/ ((A
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
IJKHLM?(O#%#(P-Q"R#D(293/(O-#Q84/%-,(!438%&'/ ((G
1(1(1(1(1(1(1(1(1(1(1(
HK1E#5#E*6#4$" &&7.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&
?15#$#6#4$"&45&GH;-I-;D&@*$>"(*L#$%&H#%$*," &&7.&.&.&.&.&.&.&.&.&.&

Table of Contents ###
!"#$%&*&H12#1"&M&789:;<=&)4>+,1 &&7.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&
U$$&8<-\ ()*+&,%-.&/ ((I1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
=&$9#,-8Q(#(;&'-&/(U(74<39&(R-%"(#(;&'-&/(>(74<39& ((I
1(1(1(1(1(1(1(1(1(1(
;&%%-8Q
(%"&(!4@@38-,#%-48()$%-48(;R-%," ((01(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
;R-%,"(U//&@*9D(;:LIV(=;L0A0L!(S-8T(B&#%3'&/ ((A
1(1(1(1(1(1(1(1(1(1(1(
;R-%,"(U//&@*9D(;:L0V(B4'(B3%3'&(E/& ((G
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
;R-%,"(U//&@*9-&/(;:LA(#8<(;:V(F4<&(F3@*&' ((H
1(1(1(1(1(1(1(1(1(1(1(
;R-%,"(U//&@*9D(;:LHV(F&%R4'T(S-8T(!4@@38-,#%-48(=#%& (([
1(1(1(1(
;R-%,"(U//&@*9D(;:L[V
=;L0A0L!(!4@@38-,#%-48(=#%&(#8<(O-#Q84/%-,(!4@@#8</ (([
1(
7438%-8Q(%"&(IJKHLM?(74<39& ((J
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
7#T-8Q(!488&,%-48/(%4(%"&(;&'-&/(U(IJKHLM? ((K
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
C$612K24E1""42&M>>21""#$% &&7.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&.&
U$$&8<-\(U<<'&//-8Q ((I1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
P4R(%4(U<<'&//(#(2S!LH(B'4@(#(2S!L0 ((I
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
U<<'&//-8Q(#(2S!LH(B'4@(#(2S!LA ((G
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(
!4@@38-,#%-8Q(B'4@(#(!4@$3%&'(%4(#(2S!LH ((H
1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(1(

!"#$%&'()
*+,-.(/",+(0#-1#2
After reading this chapter, you should know:
if this manual contains the information you need
where to locate information in this manual
where to locate information on related products
This manual describes the 1785-KE Data Highway Plus RS-232-C
Interface Module. It gives you procedures for:
installing the 1785-KE
troubleshooting your 1785-KE
For more information on programming and troubleshooting Data Highway
Plus and Data Highway interface modules, refer to the Data Highway/Data
Highway Plus Protocol and Command Set Reference Manual (publication
1770-6.5.16).
You should read this manual before attempting to install or use the
1785-KE. We assume that you are already familiar with:
RS-232-C standards and practices
your RS-232-C device or modem
Allen-Bradley Programmable Logic Controllers (PLCs)
!"#$%&' (345&6%,7&+
81'$9+&(9:(/",+(0#-1#2
;"9(<"912=(>&#=(/",+
0#-1#2

!"#$%&'(#"&)*$+*,
!"#$%&'()
1–3
This manual describes both Series A and Series B versions of the 1785-KE
module. Table 1.A lists the Series B enhancements to the module. These
features were not available on the Series A version of the module. Where
we describe these features later in the manual, we note that they are only
available on the Series B version of the module. You can see the catalog
number and the series level of the module on the name plate on the side of
the module.
/#42& ()?@
<&',&+(A(B-"#-6&C&-%+
D&#%1'& A&-&:,%
-./01.&2334.""#$%&5*6*7#,#18
9:+,,&;+6,.<&=6.4*1#0$>
?$(*[email protected]&@0//+$#@*1#0$"&@*6*7#,#18
A04&*66,#@*1#0$"&#$B0,B#$%&60#$1&10&60#$1
/03./&,#$C"D
-./01.&2334.""#$%&5*6*7#,#18
9E*,A&;+6,.<&=6.4*1#0$>
?$(*[email protected]&@0//+$#@*1#0$"&@*6*7#,#18
A04&*66,#@*1#0$"&#$B0,B#$%&/+,1#3406
/03./&,#$C"D
The Series B version of the 1785-K module uses different communication
option switches and has a different front cover and Data Highway Plus
connectors than the Series A version. Information on setting the Series A
is included in Appendix C for reference.
In this manual, we use the following terms:
/",+(/&'CF0&#-+F
;*1*&E#%(G*8&H,+" A04/.4,8&H..4&50//+$#@*1#0$"&I#$C
9H5I>
,#$C *&;*1*&E#%(G*8&04&;*1*&E#%(G*8&H,+"
$.1G04C
,0@*,&$03. $03.&0$&,0@*,&,#$C
4./01.&$03. $03.&0$&4./01.&,#$C
<&',&+ (A(B-"#-6&C&-%+
D'&E1&-%2F(*+&=(/&'C+

!"#$%&'(#"&)*$+*,
!"#$%&'()
1–4
In this manual, you will see:
WARNINGS to tell you where you may be injured if you do not follow
procedures properly
CAUTIONS to tell where equipment may be damaged if you do not
follow procedures properly
Important notes that stress information that is critical to your
understanding and use of the product
The 1785-KE Data Highway Plus RS-232-C Interface Module is part of
the Data Highway Plus product family. Related products include:
8'9=16% !#%#29.((G1C4&'H
;*1*&E#%(G*8&04&;*1*&E#%(G*8&H,+"J&&2"8$@(40$0+"
9-KLMNML5&04&-KLOMML2>&P$1.4A*@.&)03+,.
QRRSLT:M
;*1*&E#%(G*8&H,+"&10&;*1*&E#%(G*8&QRUVLT2&P$1.4A*@.
)03+,.
QRUVLT2
;*1*&E#%(G*8&H,+"&HI5LM&:*/#,8&50//+$#@*1#0$
23*61.4&)03+,.
QRUVLT2N
HI5LN&PJ=&K@*$$.4&50//+$#@*1#0$&23*61.4&)03+,. QRRVLKVWLK-V
P$3+"14#*,&'.4/#$*,&K8"1./ QRUOL'VS
HI5LV&:*/#,8&H40%4*//*7,.&50$140,,.4" K.4#."&QRUV
8'&6#1%,9-#'F(G9%&+
>&2#%&=(8'9=16%+

!"#$%&'(#"&)*$+*,
!"#$%&'()
1–5
For more information on the 1785-KE and the Data Highway Plus
network, refer to the following documents:
8142,6#%,9-F8142,6#%,9-(G1C4&'H
;*1*&E#%(G*8&H,+"&=B.4B#.G&H403+@1&;*1* QRUVLMDX
;*1*&E#%(G*8J;*1*&E#%(G*8&H,+"&H4010@0,&*$3
50//*$3&K.1&!".4Y"&)*$+*,
QRRSLXDVDQX
;*1*&E#%(G*8&5*7,.&2""./7,8&*$3&P$"1*,,*1#0$&)*$+*, QRRSLXDMDQ
The publications in the table above are available from Allen-Bradley.
Contact your local Allen-Bradley sales office for more information.
>&2#%&=($142,6#%,9-+

!"#$%&'()
*+&'+,&-(./(%"&(0123456(#78
9#%#(:,;"-#<(=>?@
In this chapter, we give you an overview of the 1785-KE module and how
it interfaces with a Data Highway Plus network.
The 1785-KE module is a communication interface that links an intelligent
RS-232-C (asynchronous) device to an Allen-Bradley Data Highway Plus
network. The 1785-KE gives you a choice of full duplex (unpolled) or
half duplex (polled) protocol on its asynchronous link.
Figure 2.1 shows the 1785-KE module’s hardware features:
diagnostic indicators
connector for the Data Highway Plus
connector for the T50 Industrial Terminal
connector for an RS-232-C device
!"#$%&' (*AB&C%,+&@
D"#%(,@(%"&(0123456
E.8?>&F

!"#$"%#&'()'*+#',-./012'345
63*3'7%8+&39':;<=
!"#$%&'()
2–2
G,;?'& ()H0
0123456(!.II?7,C#%,.7(J7%&'/#C&(E.8?>&
Data Highway Plus is a local area network (LAN) that allows peer-to-peer
communication among up to 64 nodes. You use Data Highway Plus when
you want to connect a small number of nodes on a common link.
Data Highway Plus provides easy re-configuration and expansion if you
want to add more nodes later.
Typically, you would use Data Highway Plus to connect PLC-5s that need
to communicate with each other frequently. For example, you would use
Data Highway Plus to connect a small group of PLC-5s (approximately 10
nodes or less) involved in a single integrated process. Larger links, or those
in looser configurations, could use a Data Highway as a common backbone
network.
Communication on a Data Highway Plus involves:
a physical link layer
software layers
D"#% (,@(9#%#(:,;"-#<(=>?@F

!"#$"%#&'()'*+#',-./012'345
63*3'7%8+&39':;<=
!"#$%&'()
2–3
The physical link layer is a set of cables and interface modules that work
together to provide a channel for communication between the various
points, called nodes, on the physical link.
A Data Highway Plus node consists of an interface to Data Highway Plus,
usually a module. (The PLC-5 processor has a Data Highway Plus
connection built in, so it does not need a separate interface module.)
The Data Highway Plus cables consist of a trunkline that can be up to
10,000 feet long and droplines that can be up to 100 feet each.
You can use your Data Highway Plus to connect such nodes as:
RS-232-C devices attached to a 1785-KE or a 1770-KF2
Data Highway modules attached (via their RS-232-C port) to a 1785-KE
or a 1770-KF2
a PLC-3 or PLC-3/10 attached to a 1775-S5,-SR5
a PLC-2 family device attached to a 1785-KA3
PLC-5s (direct connection)
a T50 industrial terminal
a 1785-KA (connected to a Data Highway network)
Figure 2.2 illustrates a typical Data Highway Plus network.
K"& (="<@,C#>(L,7M(L#<&'

!"#$"%#&'()'*+#',-./012'345
63*3'7%8+&39':;<=
!"#$%&'()
2–4
G,;?'& ()H)
N(K <$,C#>(9#%#(:,;"-#<(=>?@(!.7/,;?'#%,.7
Important: A computer connected to a 1785-KE module cannot access a
node on a Data Highway through a 1785-KA module. Also, nodes on Data
Highway cannot access a computer connected to a 1785-KE on Data
Highway Plus.
K"&(O./%-#'&(L#<&'@
Both Data Highway Plus and the 1785-KE’s RS-232 asynchronous link
require two layers of software to enable communication to take place. The
layers are defined as follows:
Application layer -- controls and executes the actual tasks, or
commands, specified in the communication between nodes.
Data link layer -- controls the flow of communication over the physical
link by establishing, maintaining, and releasing the communication
channel between nodes.

!"#$"%#&'()'*+#',-./012'345
63*3'7%8+&39':;<=
!"#$%&'()
2–5
The 1785-KE module automatically takes care of the data link layers on
the Data Highway Plus network.
This means that your application programs at the PLCs and computers do
not need to bother with inter-node protocol, handshaking, or control of the
Data Highway Plus link.
You must program these layers, however, for the asynchronous link
between your 1785-KE and its RS-232-C device. This programming
allows your computer to communicate with the Data Highway Plus
network, through the asynchronous link.
For more information on the commands, protocols, and diagnostics used
on your Data Highway Plus network, refer to the Data Highway/Data
Highway Plus Protocol and Command Set User’s Manual (publication
1770-6.5.16). This manual contains the information you need to program
the software layers for your computer and troubleshoot your network.
K"&(9#%#(:,;"-#<(=>?@(='.%.C.>
The Data Highway Plus link has a communication rate of 57,600 bits per
second. The Data Highway Plus implements peer-to-peer communication
with a token passing scheme to rotate link mastership among its stations.
Since this method does not require polling, it is time efficient. The Data
Highway Plus uses factory set timeouts to rebuild the token pass network if
a token is lost because of a defective station. This timeout is not adjustable.
K"&(PO4)Q)4!(N@<7C"'.7.?@(L,7M(='.%.C.>@
The 1785-KE’s RS-232 asynchronous link has a selectable communication
rate from 110 bits per second to 19,200 bits per second. It uses a selectable
protocol of half-duplex (master-slave, polled) or full-duplex (peer-to-peer,
unpolled).
You can select the half-duplex protocol for a multidrop or point-to-point
communication link. You can select the full-duplex protocol only for a
point-to-point communication link.

!"#$"%#&'()'*+#',-./012'345
63*3'7%8+&39':;<=
!"#$%&'()
2–6
G?>>49?$>&R(='.%.C.>
The full-duplex protocol conforms closely to ANSI X3.28, combining
features of subcategories D1 (data transparency) and F1 (two-way
simultaneous transmission with embedded responses).
You can use full-duplex protocol for a point-to-point link that allows
two-way simultaneous transmission. It is relatively difficult to implement
because it requires you to use interrupts and multi-tasking programming
techniques. It is intended for high performance applications where you
need to get the highest possible throughput from the available
communication medium.
:#>/49?$>&R(='.%.C.>
Half-duplex protocol serves as an alternate to full-duplex protocol.
Half-duplex protocol is similar to full-duplex in most respects. Two major
differences are:
Half-duplex protocol provides for polling of slave stations.
Half-duplex protocol does not allow embedded responses.
Half-duplex protocol is used for a link between one master and one or
more slaves. You must use modems for this type of link (unless there is
only one slave). The 1785-KE module has slave mode capability only. You
must provide the master function through a computer, or the 1771-KGM
module.
Half-duplex protocol provides a lower effective utilization of resources
compared to full-duplex, but it is easier to implement. You should use
half-duplex protocol if:
you are using multidrop modems to connect multiple slave stations to a
single master computer.
you are using moderns that have only half-duplex capability.
you are willing to sacrifice data throughput in exchange for ease of
implementation.

!"#$"%#&'()'*+#',-./012'345
63*3'7%8+&39':;<=
!"#$%&'()
2–7
If any node on a Data Highway Plus network initiates multiple commands
(for example, the initiating node sets multiple bits at any time), the order
in which those commands get executed at the remote node cannot be
guaranteed. The initiating node, the network, and the receiving node
execute commands based on network conditions, including but not limited
to:
nodes buffering commands
retries due to noise on the network
If your application requires that commands be delivered in a specific order,
your logic must control the initiation of one command at a time on the
network and verify delivery before initiating additional commands. This
verification is completed by:
a done bit or an error bit in a PLC
a reply message in a computer
A done bit or a successful reply should cause the next command to be
initiated. If an error bit or a reply with non-zero status is returned, you
must decide the appropriate action based on your application.
9&>,+&'<(*'8&'(./(!.II#78@

!"#$"%#&'()'*+#',-./012'345
63*3'7%8+&39':;<=
!"#$%&'()
2–8
Three typical applications of the 1785-KE are discussed in this manual:
connecting a computer or other intelligent device to Data Highway Plus
via an RS-232-C point-to-point link (local mode, full- or half-duplex
protocol option).
connecting two Data Highway Plus networks together over a
point-to-point modem link (remote mode, full-duplex protocol option).
connecting a Data Highway Plus node (such as a PLC-5) as a slave on a
multidrop link with a modem (remote mode, half-duplex slave protocol
option).
These are discussed in more detail later in Chapter 5, “Communicating
through the 1785-KE Module”. A short discussion of each application
follows:
Figure 2.3 shows an example of using a 1785-KE to attach a computer or
other intelligent RS-232-C device to Data Highway Plus. You attach the
computer to Data Highway Plus using a point-to-point RS-232-C link.
Figure 2.3 shows the following three options using:
a short (50 feet or less) RS-232-C link
the AB-longline RS-232-C option
a point-to-point modem link
Refer to Chapter 4 for more information on these RS-232-C options.
G,;?'& ()HQ
=.,7%4%.4L,7M@(%.(#(9#%#(:,;"-#<(=>?@(S&%-.'M
N$$>,C#%,.7@

!"#$"%#&'()'*+#',-./012'345
63*3'7%8+&39':;<=
!"#$%&'()
2–9
You can use either full-duplex or half-duplex for the RS-232-C link.
Figure 2.4 shows an example of using a 1785-KE (series B) to connect two
Data Highway Plus networks over a point-to-point modem link. You must
set the 1785-KE for full-duplex protocol in this application.
G,;?'& ()HT
!.II?7,C#%,.7(U&%-&&7(K -.(P&I.%&(9#%#(:,;"-#<(=>?@(S&%-.'M@

!"#$"%#&'()'*+#',-./012'345
63*3'7%8+&39':;<=
!"#$%&'()
2–10
Figure 2.5 shows an example of using the 1785-KE (series B) to connect a
Data Highway Plus node (such as a PLC-5) to a multidrop network. The
PLC-5 acts as a slave on the multidrop link. You must set the 1785-KE for
half-duplex protocol and use modems.
G,;?'& ()H3
E?>%,8'.$(S&%-.'M,7;(V@,7;(%"&(0123456(WO&',&@(UX

!"#$%&'()
*+,%#--.+/(%"&(0123456
This chapter explains how to install the 1785-KE module. There are four
parts to installation:
setting the communication option switches
mounting the module
connecting the module to the Data Highway Plus link
powering up your module
Refer to Chapter 4 for information on how to connect your RS-232-C
device to the 1785-KE module.
Read the first two chapters of this manual carefully before attempting to
install the 1785-KE.
Important: The Series B version of the 1785-KE module uses different
communication option switches, has a different front cover, and has
different Data Highway Plus connectors than the Series A version. This
chapter describes the Series B version. Information on setting the Series A
communication option switches and making connections to the Series A is
included in Appendix C for reference.
The 1785-KE module has 4 switch assemblies (figure 3.1) that enables you
to select various communication options. The switch assemblies and their
corresponding options are:
7&-&8%(%".,
79.%8"(:,,&;<-=>
?@'(%".,
!@;;A+.8#%.@+(B$%.@+>
!"#$ %!#&'&#()*+,-)./0123/4
!"#& 567/),289/3
!"#' #:010);+<=>0?)@*24)0,7)%!#&'&#()*+,-)A6882,+A01+6,)301/4
BC6A0*D3/861/)6E1+6,
!"#F %/4/3G/7
!"#$%&' (B<C&8%.D&,
7&%%.+/(%"&(!@;;A+.8#%.@+
B$%.@+(79.%8"&,

H,410**+,<)1=/)$IJK#LM
!"#$%&'()
3–2
?./A'& ()E0
F@8#%.@+(@G(%"&(79.%8"(:,,&;<-.&,(@+(%"&(0123456(H@IA-&
Important: The 1785-KE Series B uses the convention DOWN
(ON) = Binary 0, and UP (OFF) = Binary 1.