Data type definitions
49
SIPROTEC PROFIBUS-DP - Communication profile
C53000-L1840-B001-03
3.4 Measured value (signed integer)
Number of
byte-values
2
Range of values -32768 to +32767
(-32768 = 8000
hex
= “Overflow” or “Invalid”)
Figure 3-4 Data type: Measured value (signed integer)
Status bit (S) • Sign bit, active if negative measured value
Negative measured values are transmitted in the two's complement, i.e:
-1 = FFFF
hex
, -2 = FFFE
hex
, ..., -32767 = 8001
hex
• Status bit = 1 and measured value = 0
(i.e. transmission of the value 8000
hex
= -32768):
Measured value overflow or invalid measured value.
Byte 1 (MSB) Byte 0 (LSB)
S
Measured value
Message head ... ... Message end
Note:
The value -32768 for signalling of "Overflow" or "Invalid" is only used for measured
values in input direction.
If an evaluation of the status of a measured value in output direction is required in the
SIPROTEC device then a separate position in the PROFIBUS-DP message is to be
used for this.
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