5.3.
BCC Checksum
As a means of error detection, a block check character (BCC) checksum is added to the RS -485 communication function
of the AM-215A panelmeter. See the following illustrations for details on the transmission and reception formats.
6. Communication Commands
User’s Manual AM-215A Series RS-485
3/8
STX
D
S
P
ETX
A
E
CR
LF
Example of BCC Checksum for Transmission
Character
Hexadecimal
02H
44H
53H
50H
03H
41H
45H
0DH
0AH
BCC H = Higher-order 4 bits among the lower-order 8 bits of
the sum of the hexadecimal values numbered from [1] to [4]
44H+53H+50H+03H=EAH
[1]
[2]
[3]
[4]
BCC L = Lower-order 4 bits among the lower-order 8 bits of
the sum of the hexadecimal values numbered from [1] to [4]
44H+53H+50H+03H=EAH
Example of BCC Checksum for Reception
Character
STX
0
0
0
ETX
9
D
CR
LF
02H
30H
30H
30H
03H
39H
44H
0DH
0AH
[5]
[6]
[7]
[11]
20H
[1]
[2]
[3]
5
35H
[4]
20H
20H
H
48H
[8]
[9]
I
49H
[10]
20H
BCC L = Lower-order 4 bits among the lower-order 8 bits of the
sum of the hexadecimal values numbered from [1] to [11]
20H+20H+20H+35H+30H+30H+30H+20H+48H+49H+03H=1D9H
BCC H = Higher-order 4 bits among the lower-order 8 bits of the
sum of the hexadecimal values numbered from [1] to [11]
20H+20H+20H+35H+30H+30H+30H+20H+48H+49H+03H=1D9H
Function
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Char.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Char.
Length
Length
D
S
P CR LF
3
5
0
0
0
H
I
CR LF
10
(+ reading, w/o decimal point)
-
5
0
0
0
H
I
CR LF
10
(- reading, w/o decimal point)
5
0
0
.
0
H
I
CR LF
11
(+ reading, w/ decimal point)
<
=
9
8
0
0
H
I
CR LF
10
(+ overrange reading, w/o decimal point)
<
=
-
9
8
0
.
0
H
I
CR LF
11
(- overrange reading, w/ decimal point)
Measured value response
M
E
S CR LF
3
0
CR LF
12
(+ reading, w/o decimal point)
0
.
0
1
CR LF
12
(+ reading, w/ decimal point)
-
1
CR LF
12
(- reading, w/o decimal point)
-
0
.
0
0
5
CR LF
12
(- reading, w/ decimal point)
<
=
9
8
0
.
5
CR LF
12
(+ overrange reading, w/ decimal point)
<
=
-
9
8
0
.
5
CR LF
12
(- overrange reading, w/ decimal point)
All responses are the fixed length of 12 characters.
Comparison results response
J
G
M CR LF
3
H
I
CR LF
15
(In HI, a judgment result is.)
G
O
CR LF
15
(In GO, a judgment result is.)
L
O
CR LF
15
(In LO, a judgment result is.)
H
.
H
I
CR LF
15
(In HH and HI, a judgment result is.)
L
O
.
L
L
CR LF
15
(In LO and LL, a judgment result is.)
Hold remote control response
S
T
H CR LF
3
S
T
A
R
T
CR LF
6
(Response with the status of the hold function being set to OFF
by remote control)
H
O
L
D
CR LF
6
(Response with the status of the hold function being set to ON
by remote control)
Hold terminal response
E
S
A CR LF
3
S
T
A
R
T
CR LF
6
(Response with the status of the hold function being set to OFF)
H
O
L
D
CR LF
6
(Response with the status of the hold function being set to ON)
Hold remote control
S
T
H
S CR LF
5
Y
E
S
CR LF
5
(Sets the hold function to OFF.)
S
T
H
H CR LF
5
Y
E
S
CR LF
5
(Sets the hold function to ON.)
Trigger input
T CR LF
1
5
0
0
.
0
H
I
CR LF
11
(+ reading, w/ decimal point)
Note: The response is the same as that of “DSP”.
Hold remote control cancellation
E
S
M CR LF
3
Y
E
S
CR LF
5
Measured value and comparison
results response
