27
Byte n
Byte n+1
Byte n+2
Byte n+3
Bit7
Bit6
Bit7
Bit6
Bit7
Bit7
VZ
2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
2
-1
2
-2
2
-3
2
-4
2
-5
2
-6
2
-7
2
-8
2
-9
2
-10
2
-11
2
-12
2
-13
2
-14
2
-15
2
-16
2
-17
2
-18
2
-19
2
-20
2
-21
2
-22
2
-23
Exponent
Mantissa
Mantissa
Mantissa
Quality Quality-Substatus Limits
Gr
Gr QS QS QS QS Qu Qu
2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
0
0
= bad
0
1
= uncertain
1
0
= good (Non Cascade)
1
1
= good (Cascade) - not supported
S
Stta
attu
us
s =
= b
ba
ad
d
0
0
0
0
0
0
= non-specific
0
0
0
0
0
1
= configuration error
0
0
0
0
1
0
= not connected
0
0
0
0
1
1
= device failure
0
0
0
1
0
0
= sensor failure
0
0
0
1
0
1
= no communication (last usable value)
0
0
0
1
1
0
= no communication (no usable value)
0
0
0
1
1
1
= out of service
3.5 Profile
The MFC300 PROFIBUS MBP Interface is based on PROFIBUS PA Profile Version 3.01 and sup-
ports the following blocks:
•
One Physical Block.
This block contains the parameters defined in PA Profile 3.01.
•
One Transducer Block for coriolis mass flow devices.
This block provides the parameters and functions defined in PA Profile 3.01.
•
Eight “Analog Input (AI)” function blocks: as default “Mass Flow”, “Density”, “Medium
Temperature”, “Volume Flow”, “Concentration 1”, “Concentration 2”, “Concentration Mass
Flow 1” and “Concentration Mass Flow 2”.
•
Three “Totalizer (TOT)” function blocks: as default the first and the third totalizers will
totalize “Mass” and second one will totalize “Volume”.
3.6 Data Structure of Function Block Output Values
The data structure of function block outputs consists of 5 bytes: a 4 byte float value (Float
Format according IEEE Standard 754 Short Real Number) followed by a 1 byte status value. If
all 11 function block outputs have been projected (see above), 55 byte will be transmitted.
Float Value
First an example of the float format
Example:
40 F0 00 00 (hex) = 0100 0000 1111 0000 0000 0000 0000 0000 (binary)
Formula:
Value
= (-1)VZ * 2 (Exponent - 127) * (1 + Mantissa)
Value
= (-1)0 * 2 (129 - 127) * (1 + 2
-1
+ 2
-2
+ 2
-3
)
Value
= 1 * 4 * (1 + 0,5 + 0,25 + 0,125)
Value
= 7,5
S
Stta
attu
us
s V
Va
allu
ue
e
The meanings of the status byte (unsigned integer) are described in the following tables
