INFICON HPG400 ATM to High-Vacuum Gauge - Manual (Page 29)

tina31e1 (2004-05) HPG400 v1.om
29
Bit 1 Bit 0 Definition
0 0 Emission off
0 1 Emission on
Bit 2 Definition
0 1000 mbar adjustment off
1 1000 mbar adjustment on
Bit 3 Definition
0
⇔ 1 Toggle bit, changes with every
string received correctly
Bit 5 Bit 4 Definition
0 0 Current pressure unit mbar
0 1 Current pressure unit Torr
1 0 Current pressure unit Pa
Bit 7 Bit 6 Definition
x x Not used
Bit 3 Bit 2 Bit 1 Bit 0 Definition
x x x x Not used
Bit 7 Bit 6 Bit 5 Bit 4 Definition
0 1 0 1 Pirani adjusted poorly
1 0 0 0 Hot cathode error
1 0 0 1 Pirani error
The software version of the gauge can be calculated from the value of byte 6 of the
transmitted string according to the following rule:
Version No. = Value
Byte 6
/ 20
(Example: According to the above formula, Value
Byte 6
of 32 means software ver-
sion 1.6)
The pressure can be calculated from bytes 4 and 5 of the transmitted string. De-
pending on the measuring range (hot cathode or Pirani) and the currently selected
pressure unit (
→ byte 2, bits 4 and 5), the appropriate rule must be applied.
As result, the pressure value results in the usual decimal format.
Measuring range hot cathode
(Range of values for byte 4 and 5 = 16666
dec
… 48666
dec
)
p = 10 (high Byte × 256 + low Byte) / 5333.3) - k1
Where Pressure unit k1
mbar 9.125
Torr 9.249903
Pa 7.125
Measuring range Pirani
(Range of values for byte 4 and 5 = 54000
dec
… 60666
dec
)
p = 10
(high Byte × 256 + low Byte) / 1333.3) - k2
Where Pressure unit k2
mbar 42.5
Torr 42.624903
Pa 40.5
Status byte
Error byte
Software version
Calculation of the
pressure value