Burkert Type SE56 - Manual (Page 14)

TECHNICAL MANUAL Rev. Pagine 14/52
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03 PROFIBUS DP MODULE- DATA LINK
DESCRIPTION
Document Data Date Date
File name ProfibusDP_emanual_Burkert_04.doc 19/03/08 19/03/08 19/03/08
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on the instrument display however, it is necessary to calculate the decimal figures with a rather complex
algorithm which takes account of instrument precision, flow rate measurement unit, etc. For this purpose
and to avoid useless calculations, the number of decimals to use to represent the flow rate values is supplied
separately. With the acyclic service it is possible to return the value ( see Acyclic Index Read = 20(dec)
Static Process Data of the Flow Meter byte position 13).
NOTE:The counters are expressed with a 32 bit integer. The «counter decimal figures» parameter, indicates
the point position starting from the right: 0 = no decimal, 1=1 decimal figure, and so on. ( see Acyclic
Index Read = 20(dec) Static Process Data of the Flow Meter byte position 12)
2.2. DATA TYPE
The firsts four byte of the Dynamic Data Block are the information about the Flow rate or Totalizers.
With the Control byte of the Configuration in the GSD file (see the Section Slave Configuration) it is
possible to set the type of the Flow rate returned by the slave or the type of the Totalizers.
The type of the Flow rate may be in % or in technical unit in base of the value of the Control byte inserted
in the Configuration string.
The byte 7 indicate the current type of Flow rate selected or the type of the totalizers:
byte 7 = 0 --> Flow rate in %
byte 7 = 1 --> Flow rate in technical unit
byte 7 = 2 --> totalizers positive or batch quantity ( batch quantity only for ML M3F )
byte 7 = 3 --> partial totalizers positive or batch counter ( batch counter only for ML M3F )
byte 7 = 4 --> totalizers negative or batch quantity ( data valid only for ML 210 )
byte 7 = 5 --> partial totalizers negative or batch counter ( data valid only for ML 210 )
There is a second way to set the type of the Flow rate using the Acyclic Service during data exchange (see
section Acyclic Service).
2.3. SECOND CONFIGURATION: 16 BYTE INPUT
Below there is a description of the contents of each byte:
bytes 0-3: (32 bit single precision IEEE floating point, MSB first) Flow rate in % or Flow rate in t.u. (see
section 2.4 Data Type)
bytes 4-7: (32 bit long integer, MSB first) totalizer for TOTAL volume + or - or batch quantity (see section
2.4 Data Type)
bytes 8-11: (32 bit long integer, MSB first) totalizer for TOTAL or PARTIAL volume + or - or batch counter
(see section 2.4 Data Type)
bytes 12-13: (16 bit unsigned integer, MSB first) process flags:
bit 0 =1 if the excitation is too fast for the sensor connected
bit 1 =1 if the maximum alarm is active
bit 2 =1 if the minimum alarm is active
bit 3 =1 if the Flow rate exceeds the scale range value (overflow)
bit 4 =1 if one or more output impulses are saturated (too many impulses to emit)
bit 5 =1 if the measurement signal is highly disturbed or if the sensor is disconnected
bit 6 =1 if the measurement tube is empty
bit 7 =1 if the circuit powering the coils is not working or the sensor is disconnected
bit 8 =1 if the second measurement scale is active
bit 9 =1 if the Flow rate is lower than the cut-off threshold
bit10=1 if the Flow rate is negative