Yamato Scientific CLH600 Cool Line - Manual (Page 33)

30
Operation Method
RS485 Communication Function
2. Data Transmission Method
Item Specification
Communication standard EIA standard, complying with RS-485
Synchronization method Asynchronous communication method
Communication method Half-duplex communication
Transmission code ASCII code
Baud rate 1200/2400/4800/9600BPS
Communication distance Max. 500 m (It depends on the effect of the ambient environment.)
Network Multi-drop method (up 1:31 stations)
Signal wire Two wires for transmission and receipt
Stop bit length 1/2bits
Data length 7/8bits
Parity None/Odd/Even
BCC check Enabled/Disabled
Response delay time 0 to 250msec
Communication address 1 to 99 stations (however, 1:31 stations at maximum)
Communication mode switching RO/RW
Note) The shading indicates the initial setting of the unit.
3. Transmission Control Characters
Symbol Name Code Detail
STX Start of text 02H Indicates the start of the text.
ETX End of text 03H Indicates the end of the text.
R Read 52H The command to read a request.
W Write 57H The command to write a request.
ACK Acknowledge Character 06H Transmits a reply when data is properly received.
NAK Negative Acknowledge 15H Transmits a replay in case of a receiving error.
Note)
R: Read (command to read settings or measured values)
W: Write (command to write set values)
R commands can be communicated at all times in all modes.
W commands can be communicated in regular mode only, and the parameters that can be set
depend on the operation state (during operation). See "7. List of Identifiers/Commands."
4. Transmission Control Procedures
4.1 Communication Procedure
・ This unit returns a "reply message" to a "request message" from the host computer but does not start
transmission.
・ This unit does not start communication (no reply) for about four seconds after the power is turned on.
Set a delay until communication begins after the power is turned on.