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Using the bdlc protocol – Siemens SIMATIC TIWAY 1 User Manual

Page 202

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USING THE BDLC PROTOCOL

UNILINK HOST ADAPTER

B–17

USER MANUAL

Example B–3 Block Checksum Transmitter Calculation

DLE–STX

Address

Control

Information

BCS

DLE–ETX

1002

01

93

1003

“SNRM”

(Note: All values are in hexadecimal notation.)

BCS

0

1

2

3

4

5

6

7

8

9

10 12 13 14 15

MSB

LSB

Bit

Frame
Byte

BCS
MSB

BCS
LSB

01

00
01

00
01

93

94
2A

95
95

Complement
the MSB

The BCS is then D595

D5