10
CMVLC401A
Commissioning
5
LECOM Protocol Details
5.1
LECOM - A/B Protocol Description
The LECOM-A/B protocol is used to exchange data between SMV controllers and a host. The LECOM-A/B protocol is
based on DIN 66019, ISO 1745 and ANSI X3.28 (category 2.5 and A2, A4). These standards are similar to each other
and describe the control mode of a transmission section of a transmission system.
The host (the master) can communicate with a slave (SMV controller) in three modes:
• RECEIVE (refer to 6.2)
• SEND (refer to 6.3)
• BROADCAST/MULTICAST (refer to 6.4)
The controllers communicate by means of the ASCII code:
0
1
2
3
4
5
6
7
8
9
0
B
C
D
I
F
0
NUL
SOH
STX
ETX
EOT
ENQ
ACK
BEL
BS
TAB
LF
VT
FF
CR
SO
SI
1
DLE
DC1
DC2
DC3
DC4
NAK
SYN
ETB
CAN
EM
SUB
ESC
FS
GS
RS
US
2
space
!
“
#
$
%
&
‘
(
)
*
+
,
-
.
/
3
0
1
2
3
4
5
6
7
8
9
:
;
<
-
>
?
4
@
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
5
P
Q
R
S
T
U
V
W
X
Y
Z
[
\
]
^
_
6
‘
a
b
c
d
e
f
g
h
i
j
k
I
m
n
o
7
p
q
r
s
t
u
v
w
x
y
z
{
I
}
~
DEL
Example:
“EOT”
= 02
hex
= 2
dec
Character “ 1” = 31
hex
= 49
dec
5.2
Controller address (AD1, AD2)
One or more bus devices (slaves) can be selected by means of the controller address, which is 2 bytes (AD1, AD2) long.
The LECOM-A/B protocol supports the broadcast telegrams, i.e. a telegram is sent to a group or all other bus devices.
For this, controller addresses are reserved (refer to BROADCAST, 6.4). Controller addresses have the following structure:
AD1
AD2
The abbreviations have the following meanings:
AD1
ASCII ten-digit of the slave address (0 ... 9; 30 ... 39
hex
)
AD2
ASCII one-digit of the slave address (0 ... 9; 30 ... 39
hex
)
