INFICON PSG55x ATM to Medium Vacuum Gauge (Profibus) - Manual (Page 38)

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tira56e1 (2010-02) PxG55x.cp
The Block Type ID Parameter contains an ID which describes the block type. The
block type ID of the "Sensor Analog Input Function Block" is set to "2". The other
defined block types are listed in Appendix B.
The process value contains the measurement value of the Heat Transfer Vacuum
Gauge (Pirani) transducer instance, transformed on the basis of the chosen data
unit. If the device is not in state EXECUTING (ID 25, Device Block), the Process
value is set to the value specified by the Safe State (ID 39). This could be the Safe
Value, Last Value, Full Scale, Zero, device specific, or vendor specific.
Conversion between different Data Units:
p [mbar] = p [Torr] * 1.33322369
p [Torr] = p [mbar] / 1.33322369
p [Pa] = p [Torr] * 133.322369
Conversion between different Data Types:
p [Counts] = 3511 * log (p [mbar] * 2 20 ) + 1
p [mbar] = 10 ((p [Counts] - 1) / 3511) / 2 20
This parameter provides the Alarm and Warning State of this block instance.
Because Alarm and Warning Trip Points are not implemented, this value is always
"0".
This parameter determines the data type of ProcessValue and all related
parameters. Two data types are supported: Float and Integer16.
This parameter can be changed via master class 2 acyclic data transfer only if the
device is not in cyclic data transfer with master class 1. The data type is valid for all
block instances of the device. This means that all parameters determining the data
type will have the same value. A change of one data type parameter changes all
others to the same value.
It is possible to adjust the data type during cyclic data transfer start up (setting of
configuration data, CFG-String. In this case the data type value is updated with the
value requested by the configuration data.
The data type can be changed from Float to Integer16. After startup it is set to the
value stored in the EEPROM. The default setting is "Float".
Coding Data type
3 INT16
8 FLOAT
(default)
The device supports the four data units described below:
Coding (hex) Unit
1001 COUNTS
1301 Torr
1308 mbar
1309 Pascal
For safety reasons, it is not possible to change the pressure unit while
the gauge is cyclically interchanging data with a DP/V0 master.
The data unit setting can only be modified when the gauge is in the IDLE
status.
In cyclic data traffic, the data unit must be set in the User Parameter
Data. All settings previously made in acyclic data traffic are overwritten.
→ 12 "User Parameter Data"
If the data unit is set in one instance, that data unit setting applies to all
instances. Likewise, the data unit setting made in the User Parameter
Data is valid for all instances.
8.2.2 Block Type ID (ID 16)
8.2.3 Process Value (ID 19)
8.2.4 Status (ID 20)
8.2.5 Data Type (ID 21)
8.2.6 Data Unit (ID 22)