Bosch Rexroth OptiFeed-FS EcoDrive 03 FLP04VRS - Generating the Checksum

10-20 Interface ECODRIVE03-FL*-04VRS
DOK-ECODR3-FL*-04VRS**-FK01-EN-P
Generating the Checksum
Examples: 1. #_N0000_POI _ 1_ _ _ _ +123456,789_123_ $
2. #5N0123_NOP _ _$
Character Hex
∑ Hex
Character Hex
∑ Hex
# 23 23 # 23 23
_ 20 43 5 35 58
N4E91 N 4EA6
030C1 0 30D6
0 30 F1 1 31 107
0 30 121 2 32 139
0 30 151 3 33 16C
_ 20 171 _ 20 18C
P 50 1C1 N 4E 1DA
O 4F 210 O 4F 229
I 49 259 P 50 279
_ 20 279 _ 20 299
1 31 2AA _ 20 2B9
_202CA
_202EA
_ 20 30A
_ 20 32A
+ 2B 355
1 31 386
2323B8
3333EB
4 34 41F
5 35 454
6 36 48A
.2E4B8
7374EF
8 38 527
9 39 560
_ 20 580
1315B1
2325E3
3 33 616
_ 20 636
Fig. 10-16: Generating the Checksum
• The sum of all ’ASCII’ characters is calculated, from the first control
character to the last character before the ’$.’
• Then, the ’High Byte’ is added to the ’Low Byte.’ A transmission
occurring during this time is ignored.
•
The Two’s Complement of the ’Low Byte’ of this sum results in the
checksum
Example 1: #_N0000_ 1_ _ _ _ +123456,789_123_ $C4
Sum: 636 Í 06 + 36 = 3C. The Two’s Complement of 3C is C4.
Example 2: #5N0123_NOP _ _$45
Sum: 2B9 Í 02 + B9 = BB. The Two’s Complement of BB is 45.