turck BL67 - Equations for 16 Bit Representation

Appendix
D300529 0115 - BL67 I/O modules15-10
15.2.1 Equations for 16 bit representation
Current values from 0 to 20 mA
Before using the equation below, th
e hexadecimal or binary value has to be converted into a decimal
value.
The value range:
0 mA to 20 mA
is displayed as follows:
0000
hex
to 7FFF
hex
(decimal: 0 to 32767)
The hexadecimal/binary value can easily be converted into a decimal value, because all numbers
belong to the
positive range of the two’s complement (→ page 15-9).
The current value can now be calculated by means of the following equation:
current value =
dezimalerZahlenwert
1638 35,
----------------------------------------------------
mA = 6,1 × 10
4
× decimal value
Current values from 4 to 20 mA
Before using the equation below, th
e hexadecimal or binary value has to be converted into a decimal
value.
The value range:
4 mA to 20 mA
is displayed as follows:
0000
hex
to 7FFF
hex
(decimal: 0 to 32767)
The hexadecimal/binary value can easily be converted into a decimal value, because all numbers
belong to the
positive range of the two’s complement (→ Figure 15-3:).
The current value can now be calculated by means of the following equation:
current value = 4,88 x 10
-4
x decimal value + 4 mA
Temperature- and resistance values (BL67-2AI-PT)
Before using the equation below, th
e hexadecimal or binary value has to be converted into a decimal
value.
The hexadecimal/binary values for the negative value range cannot easily be converted into decimal
va
lues, because the values are coded as two’s complement (→ page 15-9).
All numerical values from 00000
hex
to 7FFF
hex
represent positive values when coded as two’s comple-
ment. Values in this range can easily be converted into decimal va
lues. This is also relevant for binary
numbers in which the most significant bit (bit 16) is "0".
All numerical values from 8000
hex
to FFFF
hex
represent negative values when coded as two’s comple-
ment. This is also relevant for binary numbers in which
the most significant bit (bit 16) is "1". The con-
version into a decimal number is sh
own in the following:
Example of the conversion of ne
gative numerical value
The following parameterization
is used in the example:
"Pt100, -200 … 150 °C"