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FS34100 User Manual
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5.4.3 Frame
The frame function is based on the standard Modbus RTU framing:
Table 5.2: frame function
Start_bits
Address Function codes
Data
CRC
Stop_bits
T1-T2-T3-T4
8 bit
8 bit
N 8 bit (20≥n≥0) 16 bit
T1-T2-T3-T4
Start_bits
:
4 periods bit time, for a new frame.
Address:
The address can be set from 1 to 255 except for 157 (0x9d). 0 is the broadcast address.
Function codes:
Define the product's functions/actions (slaves), either execution or response.
Data:
The address of the register, length of data, and the data themselves.
CRC:
CRC verification code. The low byte is followed by the high byte. For example, a 16-bit
CRC is divided into BYTE_H and BYTE_L. In the framing, the BYTE_L will come first, then
followed by the BYTE_H. The last one is the STOP signal.
Stop_bits:
4 periods bit time, for ending the current frame.
5.4.4 Function codes
The Modbus function codes applied for the product are the sub-class of the standard Modbus
function codes. These codes are used to set or read the registers of the product:
Table 5.3: function codes
Code
Name
Functions
0x03
Read register
Read register(s)
0x06
Set single register
Write one single 16-bit register
0x10
Set multiple registers
Write multiple registers
5.4.5 Registers
The product (MF4600) has multiple registers available for the assignment of the various functions. With these
functions, the user can obtain the data from the products, such as
product address
and
flow rates
from the
registers, or set the product functions by writing the corresponding parameters.
The currently available registers are listed in the following table, and the registers may be customized upon
contacting the manufacturer. Where R: read; W: write-only; W/R: read and write.
Note: At the time of shipping, the write protection function is enabled except for address and baud rate.
Once the user completes the register value change, the write protection will be automatically enabled
once again to prevent incidental data loss.