User guide

24 tira47e1 (2005-08) BPG402SPv1.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
15 AI Block Adjust
Command
Record - 2_W
19 Process Value
(PV)
Simple According to
Data Type value
(Parameter 21)
- 0_XI
1/2_R
V
20 Status Simple UINT8 1 0_XI
1/2_R
V
21 Data Type Simple UINT8 1 2_R/W N
22 Data Units Simple UINT16 2 2_R/W N
23 Reading Valid Simple Boolean 1 1/2_R V
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. After the gauge is
switched on, the value stored in the EEPROM is loaded. 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
SLOT 1 / Instance 1
3.2.2.1 Process Value ID 19
3.2.2.2 Status ID 20
3.2.2.3 Data Type ID 21