Siemens HydroRanger 200, Инструкция по эксплуатации, Страница: 115 / 280

7ML19985FC03 HydroRanger 200 – INSTRUCTION MANUAL Page 105
m
mmmm
Da
ta
T
yp
e
s
Data Types
The HydroRanger 200 parameters do not always use integers to hold values. For the
convenience of the programmer, those values are converted to and from a 16-bit integer
number. This section describes the conversion process. The sections that follow describe
where those values are in the discrete I/O and block transfer addresses, and how to get
the parameters you need.
Numeric Values
Numeric parameter values are the most common. For example, parameter P920
(Reading) returns a number that represents the current reading (either level or volume,
depending on the HydroRanger 200 configuration).
Numeric values are requested or set in units or percent of span, and may be specified
with a number of decimal places.
Numeric values must be in the range –20,000 to +20,000 to be valid. If a parameter is
requested and its value is more than +20,000, the number 32,767 is returned; if it is less
than –20,000, the number –32,768 is returned. If this overflow happens, decrease the
number of decimal places.
If a parameter cannot be expressed in terms of percent of span, or has no meaningful
value, the number 22,222 is returned. Try requesting the parameter in units, or refer to
P005 in the
Parameter Reference
section on page 120.
Bit Values
Bits are packed into registers in groups of 16 bits (1 word). In this manual, the bits are
numbered from 1 to 16, with bit 1 as the least significant bit (LSB) and bit 16 as the most
significant bit (MSB).
Unsigned Double Precision Integer (UINT32)
Large numbers are put into unsigned 32 bit integers. By default, they are set up so that
the first word (register) is the most significant word (MSW) and the second word
(register) is the least significant word (LSW).
16 15 14 13 12 11 10 09 08 07 06 05 04 03 02 01
MSB LSB