INFICON BPG402-SP ATM to Ultra-High Vacuum Gauge (Profibus) - Manual (Page 23)

tira47e1 (2005-08) BPG402SPv1.cp
23
All gauge functions of the BPG402-SP are described in the Analog Input Block.
Since the gauge includes two measuring systems, there are also two Analog Input
Block Instances representing the Pirani and the ionization measuring part (BA)
respectively.
ID Name
1)
Structure Data type Bytes Access Store
15 AI Block Adjust
Command Simple UINT8 1 1/2_W -
16 Block Type Simple Octet string 4 2_R N
46 Channel Instance
Selector Simple UINT8 1 1/2_R/W N
47 PV Selector Simple UINT8 1 0_XI
1/2_R V
1)
The above parameters are described below.
To start "Full Scale Adjust" of the gauge, the value "1" has to be entered.
The value of the Block Type ID is "3" (
→ table in Appendix A).
The gauge has two instances of the Analog Input Function Block and two instances
of the Vacuum Gauge Transducer Block, or one instance of each block per
measuring system (Pirani and BA). There are two additional instances for
describing the thresholds of the switching functions (
→ section "Analog Sensor
Input Function Block", Instances 3 and 4).
However, there is only one address range for both, querying and setting the corre-
sponding parameters. The Parameter Channel Instance Selector is used for de-
fining the parameters that are written into the address range.
If the Parameter Channel Instance Selector is set to "1", the attributes of Instance 1
are mapped into that address range and can be written or read by addressing
Slot
⇒ Instance ⇒ Parameter-ID.
The PV Selector is determined by the gauge and defines the Analog Input Function
Block Instance from which the measured value is copied into the cyclic output data
telegrams. Therefore, the value output in the cyclic data is always the measured
value of the active instance, i.e. the one that is currently measuring. While the
gauge is measuring in the BA range, the measured value of the ionization vacuum
meter is output in the cyclic data and while the gauge is measuring in the Pirani
range, the measured value of the Pirani is output.
The measured values of Instances 3 and 4 (thresholds of the switching
functions) are not output in the cyclic data.
The pressure ranges, in which measurement is performed either by the Pirani or by
the BA measuring part, and are thus called "active", are indicated below:
Pressure [mbar] PV Selector
5.5×10
-3
< p
≤ 1000 Pirani
5×10
-10
< p < 2×10
-2
BA
In the pressure range 5.5Ч10
-3
… 2Ч10
-2
mbar an averaging of the two
corresponding measurement principles is done. The active instance in this
pressure range is Pirani.
3.2 Analog Input Block
3.2.1 One Of N Analog Input
Function Block / SLOT 1
3.2.1.1 AI Block Adjust Command
ID 15
3.2.1.2 Block Type
ID 16
3.2.1.3 Channel Instance Selector
ID 46
3.2.1.3 PV Selector ID 47
Measuring range