Spectris Particle Measuring Systems LiQuilaz II E, Руководство по эксплуатации

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Page C-16 LiQuilaz II E and S Operations Manual
Appendix C Modbus TCP Protocol
Processing of 32-bit Register Value
Some parameters such as particle counts are 32 bit values. Modbus does not natively
support 32 bit data; however, it is common in industry to use two 16 bit registers to
create a single 32 bit value. Here are two methods for doing this:
• Add the value as two unsigned numbers.
Example:
[32-Bit Unsigned Reg] = [16 Bit Low Unsigned] + 65536 * [ 16 Bit High Unsigned]
• Use arithmetic OR and left- shift operation.
Example:
[32-Bit Unsigned Reg] =
([16 Bit High Unsigned] << 16-bit left-shift)
{arithmetic OR} [16 Bit Low Unsigned]
Never combine the values as signed integers or floating point value. If the final value is
signed, convert the 32-Bit Unsigned value to a 32-Bit signed value after combining the
unsigned 16 bit values. If the final value is a floating point value, interpret the final 32-
Bit value as floating point after combining the numbers as unsigned 16 bit integers.