beautypg.com

Operation method, Rs485 communication function – Yamato Scientific BB600 Low Constant Temperature Water Bath User Manual

Page 36

background image

33

Operation Method

RS485 Communication Function

5. Communication Examples

5.1 Read communication example

Example) Request message:

A request for reading PV is transmitted to the unit set at address 02.
Reply message from the unit to this request message: The data of PV (00123) is returned.


S

T

X

0 2

R

P

V

1

E

T

X

B

C
C






Code Symbol/Data

ASCII

code

*2

Start Code

STX 02H

Address

02

30H 32H

Request (Read)

R 52H

Identifier

*1

PV1

50H 56H 31H

Numeric Data

00123

30H 30H 31H 32H 33H

End Code

ETX 03H

Request

61H

BCC data

Reply

02H

Acknowledgement code

ACK 06H

*1): See "7. List of Identifiers/Commands."
*2): For ASCII codes, see "8. List of ASCII Codes."

S

T

X

0

2

A

C

K

P

V

1

0

0

1

2

3

E

T

X

B

C
C

Read request message

(transmitted from the host computer)

Reply message (returned from the unit)