INFICON BCG450-SP ATM to Ultra-High Vacuum Triple Gauge (Profibus) - Manual (Page 24)

24
tira41e1 (2005-06) BCG450SPv1.cp
Instance 1 of the Analog Sensor Input Function Blocks describes the functionality
of the Pirani measuring part of the gauge.
The following attributes are supported:
ID Name Structure Data type Bytes Access Store
19 Process Value
(PV) Simple According to
Parameter Data
Type - 0_XI
1_R
2_R D
20 Status Simple Unsigned8 1 0_XI
1/2_R D
21 Data Type Simple Unsigned8 1 2_R/W N
22 Data Units Simple Unsigned16 2 2_R/W N
23 Reading Valid Simple Boolean 1 1_R
2_R D
24 Full Scale Simple According to
Data Type value
(Parameter 21) - 1/2_R N
39 Safe State Simple Unsigned8 1 1/2_R/W N
40 Safe Value Simple According to
Data Type value
(Parameter 21) - 1/2_R/W N
44 Overrange Simple According to
Data Type value
(Parameter 21) - 1/2_R N
45 Underrange Simple According to
Data Type value
(Parameter 21) - 1/2_R N
The Process Value contains the measured value of the Pirani Device Instance in
the currently selected data unit (ID 22) and in the selected data type (ID 21).
If the device is not in the EXECUTING State (ID 25, Device Block), the value de-
fined in the Safe State is output.
Values output in the data unit COUNTS can be converted into a pressure value by
means of the following formulas:
Calculation of the pressure (PV is the abbreviation used for Process Value):
PV
mbar
= 10
(COUNTS / 2000) - 12.5
PV
Torr
= 0.75006168 × PV
mbar
PV
Micron
= 10
-3
× PV
Torr
PV
Pa
= 100 × PV
mbar
This parameter remains on "0".
Two data types are supported: Float and Integer16.
In cyclic data exchange, the data type cannot be modified. The data type setting
can only be modified when the gauge is in the IDLE status. By defining the configu-
ration data for cyclic data exchange (selection of standard telegrams), the data type
used in the selected standard telegram is taken over. All settings previously made
in acyclic data traffic are thus overwritten.
If the data type is set in one instance, that data type setting applies to all instances.
Likewise, when a standard telegram is selected, the data type used by that
standard telegram will be valid for all instances:
3.2.2 Analog Sensor Input
Function Block
Instance 1 / SLOT 1
3.2.2.1 Process Value
3.2.2.2 Status
3.2.2.3 Data Type