DK Digital CDB-700 Instruction Manual download pdf (Page 24)

5. RKC COMMUNICATION PROTOCOL

IMR02C16-E3

5.1.1 Polling procedures

(1) Data link initialization

Host computer sends EOT to the controllers to initiate data link before polling sequence.

(2) Data sent from host computer - Polling sequence

The host computer sends the polling sequence in the following formats:

1. Address (2 digits)

The device address specifies the controller to be polled and each controller must have its own

unique device address.

This data is a device address of the controller to be selected and must be the same as the device

address set value in item 4. SETTING (P. 9).

The polling address which transmitted a message once becomes effective so long as data

link is not initialized by transmit and receive of EOT.

2. Identifier (2 digits)

The identifier specifies the type of data that is requested from the controller. Always attach the

ENQ code to the end of the identifier.

For details, refer to 5.3 RKC Communication Identifier List (P. 27).

3. ENQ

The ENQ is the transmission control character that indicates the end of the polling sequence.

The ENQ must be attached to the end of the identifier.

The host computer then must wait for a response from the controller.

(3) Data sent from the controller

If the polling sequence is received correctly, the controller sends data in the following format:

1. STX

STX is the transmission control character which indicates the start of the text transmission

(identifier and data).

IdentifierAddress

Example:

ENQ

1M0

Identifier Data BCC

ETX

STX

3.2. 5. 4.1.

3. 2. 1.

ENQ

1 2 ... 19 20 21 22 23 24 25 26 27 28 29 ... 81 82

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DK Digital CDB-700 Instruction Manual Page 24