Endress+Hauser Teqwave F, Руководство по эксплуатации

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Teqwave F/I Modbus TCP System integration
Hauser 33
Register name Data type Register address Length
Density / kg/m³ IEEE754 32bit 0x0014:0x0015 2
Dispersion IEEE754 32bit 0x001A:0x001B 2
System status 32bit unsigned 0x0050:0x0051 2
While values are transmitted in "big-endian" format during Modbus communication,
in line with specifications, the content of the registers is saved in "little-endian" format
for performance reasons. The sequence of the received bytes must be reversed to
convert between big-endian and little-endian format.
Example: read concentration A
The result is a floating point number in the format IEEE754 32bit. The value is saved in
two consecutive addresses, with the first address containing the least significant word
(lower part of the mantissa) and the second address containing the most significant word
(sign, exponent and upper part of the mantissa).
To get the concentration, the following data must be sent for a query to the transmitter IP
address via port 502:
Send to transmitter: 04 0000 0002 Reply from transmitter: 04 04 F37F CE41
04: Function: Read Input Registers
(0x04) 04: Function: Read Input Registers
(0x04)
0000: Start address: 0x0000 04: Number of consecutive bytes: 0x04
0002: Number of registers to be read
(16-bit): 0x0002 F37F CE41: Floating point number in IEEE754
format (little-endian)
Result:
• Word 1, register address 0x0000, least significant word: 0xF37F
• Word 2, register address 0x0001, most significant word: 0xCE41
Little-endian to big-endian conversion:
• Word 1, register address 0x0000, least significant word: 0x7FF3
• Word 2, register address 0x0001, most significant word: 0x41CE
The result is: 0x41CE 7FF3 → 25.812475 (IEEE754 format; big-endian).