VEGA VEGASON 66 Profibus PA - Manual (Page 55)

Byte-No. 1 2 3 4 5 6 7 8 9 10
Status
Status
Status
Status
(FB1)
IEEE-754-
Floating point value
PA-OUT
(FB1)
IEEE-754-
Floating point value
Additional Cyclic
Value
Format
Value
Data format of the output signal
Byte4 Byte3 Byte2 Byte1 Byte0
Status Value (IEEE-754)
Fig. 27: Data format of the output signal
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).
The measured value is transmitted as 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. 28: Data format of the measured value
Coding of the status byte associated with the PA output value
Status
code
Description according to Profi-
bus standard
Possible cause
0x00 bad - non-specific Flash-Update aktiv
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 "Out of Service" mode switched on
Supplement
VEGASON 66 - Profibus PA 55
28789
-EN
-060731