IE-SNC-T43(4)11-02
9
is sent as eight bit data word in format: 1 start bit, 8 bit data word (LSB first), 2 stop bits, no parity.
Transducer supports communication speed from 110Bd to 115200Bd.
Sent request and response have syntax: ADDRESS OF DEVICE – FUNCTION – Modbus CRC
Supported functions
03 (0x03)
: Reading of 16-bit registers (Read Holding Registers)
04 (0x04)
: Reading of 16-bit input gates (Read Input Registers)
16 (0x10)
: Setting of more 16-bit registers (Write Multiple Registers)*
2
Jumper and button
Jumper and button are located next to connection terminals. If Modbus communication protocol is
used, the function of jumper and button is as follows:
•
Jumper opened – transducer memory is write protect, from transducer is only enabled to
read measured value, writing to memory is disabled (no change of transducer address and
communication speed is enabled)
•
Jumper closed – writing to transducer memory is enabled by means of function
16 (0x10):
Setting of several 16-bit registers (Write Multiple Registers)
•
Jumper closed and pressed button for longer than three seconds – causes restoring of
manufacturer setting of communication protocol, i.e. sets transducer address to 01h and
communication speed to 9600Bd
•
Jumper opened and pressed button – transducer goes to Info mode, see chapter „
Info mode
“
Description of supported function
03 (0x03): Reading of 16-bit registers (Read Holding Registers)
Function serves for reading of values from transducer. Addresses of available registers are listed
in chapter „
Modbus registers of the
transducer at page
14
.“
Request:
----------------------------------------------------------------------------------------------
FUNCTION
Function
code
0x03
----------------------------------------------------------------------------------------------
DATA
Initial address Hi
0x??
Initial
address
Lo
0x??
----------------------------------------------------------------------------
Number of registers Hi
0x??
Number of registers Lo
0x??
----------------------------------------------------------------------------------------------
Response:
----------------------------------------------------------------------------------------------
FUNCTION
Function
code
0x03
----------------------------------------------------------------------------------------------
DATA
Number of Bytes
0x??
----------------------------------------------------------------------------
States of register Hi
0x??
States of register Lo
0x??
...
States of register Hi
0x??
2
See detailed description of this function