
MULTI GAUGE CONTROLLER
COMMUNICATION
Example:
Set IP address at value . . .
.
Query:
TX:
F
A A
FF D B
Response:
RX:
F
F
. .
RESPONSE IN CASE OF ERROR
The Modbus protocol de ines the reaction if errors occurs. The Slave device is able to detect a
damaged query or a query which contains incorrect data. It responds then with error code.
However, transmission errors may occur to which Slave devices cannot respond. Then after waiting
the Master device will interpret the lack of response as a communication error. The Master should
then resend the query.
. . .
ERROR AND WARNING CODES
The Slave device, which detected a damaged query, or a query which contains incorrect data will
respond with an error message. An error message consists of the following elements.
Device address
Function code
Error code
CRC
byte
byte
byte
MSB LSB
The function code byte contains a transmitted function code, but with the most signi icant bit set
at (it is the result of adding
to the function code - binary
).
In response the error code indicates the type of the error detected.
The MG supports the type of the detected error:
Error
code
Error type
Description
x
Incorrect
function
Function code is incorrect for Master (or slave) device.
x
Incorrect
address
Address out of range or start/end write/read in incorrect place of ta-
ble.
x
Incorrect
data
/
argument
Data value of is inadmissible for the word addressed.
x
Device error
Error occurred in the Master or Slave device when executing the op-
eration.
x
Acknowledge
The Master (or Slave) device accepted the command and the opera-
tion is being executed. Its execution takes too long and the response
is sent back, to prevent the time limit error in the inquired device. The
Slave (or Master) may send a message in the next loop, to determine
whether the operation has been completed successfully.
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