VEGA VEGAFLEX 62 Profibus PA - Manual (Page 56)

10.2 Profibus PA - Data format and status byte
Data format of the output signal
Byte4 Byte3 Byte2 Byte1 Byte0
Status Value (IEEE-754)
Fig. 33: Data format of the output signal
Status byte:
The status byte corresponds to profile 3.0 "Profibus PA Profile for Process Control Devices" coded.
The status "Measured value OK" is coded as 80 (hex) (Bit7 = 1, Bit6 … 0 = 0).
Measured value (Value):
The measured value is transferred as a 32 bit floating point number in the IEEE-754 format.
Byte n Byte n+1
Bit
7
VZ
Exponent
Bit
6
2
Bit
5
2
Bit
4
2
Bit
3
2
Bit
2
2
Bit
1
2
Bit
0
2
Bit
7
2
Bit
6
2
Bit
5
2
Bit
4
2
Bit
3
2
Bit
2
2
Bit
1
2
Bit
0
2
Sign
Bit
Significant
7 6 5 4 3 2 1 0 -1 -2 -3 -4 -5 -6 -7
Byte n+2 Byte n+3
Bit
7
2
Significant
Bit
6
2
Bit
5
2
Bit
4
2
Bit
3
2
Bit
2
2
Bit
1
2
Bit
0
2
Bit
7
2
Bit
6
2
Bit
5
2
Bit
4
2
Bit
3
2
Bit
2
2
Bit
1
2
Bit
0
2
Significant
-9 -10 -11 -12 -13 -14 -15 -16 -17 -18 -19 -20 -21 -22 -23 -8
Value = (-1) VZ 2 (Exponent - 127) (1 + Significant)
Fig. 34: Data format of the measured value
Coding of the status byte associated with the PA output value
Status
code Description according to Pro-
fibus standard Possible cause
0x00 bad - non-specific Flash-Update active
0x04 bad - configuration error l Adjustment error
l Configuration error with PV-Scale (PV-Span too small)
l Unit irregularity
l Error in the linearization table
0x0C bad - sensor failure l Hardware error
l Converter error
l Leakage pulse error
l Trigger error
0x10 bad - sensor failure l Measured value generation error
l Temperature measurement error
0x1f bad - out of service constant "O ut of Service" mode switched on
0x44 uncertain - last unstable value Failsafe replacement value (Failsafe-Mode = "Last value" and
already valid measured value since switching on)
56 VEGAFLEX 62 • Profibus PA
10 Supplement
31839
-EN
-100426