VEGA VEGABAR 52 Profibus PA - Manual (Page 50)

50
10 Supplement
VEGABAR 52 • Profibus PA
36719-EN-130321
Examples of telegram configuration
In the following you will see how the modules can be combined and how the appendant data tel-
egram is structured.
Example 1 (standard setting) with pressure value, temperature value and additional cyclical value:
•
AI (PA-OUT)
•
Temperature
•
Additional Cyclic Value
Byte-No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Format
Value
IEEE-754-
Floating point value
PA-OUT
(FB1)
Status
Status
(FB1)
IEEE-754-
Floating point value
Temperature
(FB2)
IEEE-754-
Floating point value
Additional Cyclic
Value
Status
Status
(FB2)
Status
Status
Fig. 30: Telegram configuration example 1
Example 2 with pressure value and temperature value without additional cyclical value:
•
AI (PA-OUT)
•
Temperature
•
Free Place
Byte-No. 1 2 3 4 5 6 7 8 9 10
Format
Value
IEEE-754-
Floating point value
PA-OUT
(FB1)
Status
Status
(FB1)
IEEE-754-
Floating point value
Temperature
(FB2)
Status
Status
(FB2)
Fig. 31: Telegram configuration example 2
Example 3 with pressure value and additional cyclical value without temperature value:
•
AI (PA-OUT)
•
Free Place
•
Additional Cyclic Value
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
Fig. 32: Telegram configuration example 3
Data format of the output signal
Byte4 Byte3 Byte2 Byte1 Byte0
Status Value (IEEE-754)
Fig. 33: 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 transferred as a 32 bit floating point number in the IEEE-754 format.