Ditel RS2 Manuel De L'utilisateur page 26

PROTOCOLS DESCRIPTION
• ISO 1745 PROTOCOL
INSTRUMENT RESPONSE MESSAGE FORMAT
The typical format of messages sent from the instrument in response to a command from the master device is as
follows:
In the case of commands that request the return of a value (of the data request type):
SOH D d STX
One SOH start-of-message byte [ASCII 01].
Two address bytes.
One byte STX start of text [ASCII 02].
"N " bytes corresponding to the requested value (including sign and decimal point).
One ETX end of text byte [ASCII 03].
A control BCC byte.
In the case of commands that do not imply the return of a value (type commands or change of parameters):
D d ACK
The instrument will send a confirmation that the message has been received.
If the message has been correctly received and interpreted, the response will consist of two address bytes and
one "ACK" byte [ASCII 06].
If the received message has not been acknowledged or errors have been detected, the response will consist of
two address bytes and one "NAK" byte [ASCII 21].
When the master device transmits a message to address 00, the command will be interpreted by all devices on
the network and there will be no response.
• MODBUS RTU PROTOCOL
To use the ModBus protocol, consult the specific MODBUS manual available at
KOSMOS SERIE
X .................. X ETX
or D d
ASCII / ISO1745 COMMAND TABLE
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BCC
NAK
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RS2
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