Azbil F4Q, Руководство пользователя

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4-7
Chapter 4. CPL Communication
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RS command (decimal format consecutive data read)
z RS command instruction message
This is a command—in one message—to read the contents of consecutive data
addresses from the specified read start data address.
The application layer consists of the following three types of data.
Read instruction code
Read start data address
Read count
02H 30H 31H 30H 30H 58H 52H 53H 2CH 31H 30H 30H 31H 57H 2CH 32H 03H 39H 41H 0DH 0AH
STX 0 1 0 0 X R S , 1 0 0 1 W , 2 ETX 9 A CR LF
Data link layer Application layer Data link layer
• Data is delimited by commas (“,” = hex character code 2CH).
• The above figure shows how a single message instructs the reading of two pieces
of data (starting from address "1001").
1. Read instruction code (RS)

Role : This is the command for reading data in decimal format.

Description : Two characters, "RS" (52H, 53H).
2. Read start data address

Role : This specifies by a decimal number the first data address to read.

Description :
6 - 2 Communication Data Table (p. 6-3)
(for the
relationship between data addresses and read data)
Be sure to add “W” (57H) to the end of the data address.
3. Number of read data records

Role : This specifies by a decimal number how many consecutive data
records to read, starting from the specified data address.

Description : Up to 10 data records can be read in one message.
z Response message to the RS command
If the message in the data link layer is correct, a response message appropriate for
the contents of the instruction message is returned.
All data in the application layer is expressed in decimal character.
(However, in the case of an error response, read data is not included.)
4 - 3 Description of Commands