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Instruction Manual
7.2
Log 1-8; Log-Linear Analog Output Equation & Table - mbar
Log-Linear 1 to 8 V analog output for selected gases - Engineering units in mbar
True
Pressure
(mbar)
N
2
0.0001
1.000
0.0002
1.301
0.0005
1.699
0.0010
2.000
0.0020
2.301
0.0050
2.699
0.0100
3.000
0.0200
3.301
0.0500
3.699
0.1000
4.000
0.2000
4.301
0.5000
4.699
1.0000
5.000
2.0000
5.301
5.0000
5.699
10.0000
6.000
20.0000
6.301
50.0000
6.699
100.0000
7.000
200.0000
7.301
300.0000
7.477
400.0000
7.602
500.0000
7.699
600.0000
7.778
700.0000
7.845
760.0000
7.881
800.0000
7.903
900.0000
7.954
1000.0000
8.000
1100.0000
8.041
1200.0000
8.079
1300.0000
8.114
1333.0000
8.125
The log-linear output signal and pressure are related by the following formulas:
P = 10
where P is the pressure in mbar, and V is the output signal in volts.
An analog output of 10 volts indicates a faulty convection gauge or unplugged gauge cable.
The chart on the following page shows the graphical results of the table and formulas given above for nitrogen.
True pressure (N
) is plotted on the X-axis with a log scale. The output signal is plotted on the Y-axis on a linear scale.
2
Note - when using the units of pascals and LOG 1-8 is selected , the same equation of P = 10
applies. This results in a log-linear analog output range of 1 to 10.12 Vdc for 1.30E-02 pascals to 133 kpa.
InstruTech, Inc.
Ar
He
O
2
1.000
1.000
1.000
1.301
1.301
1.301
1.699
1.699
1.699
1.903
1.938
2.000
2.146
2.204
2.301
2.524
2.602
2.699
2.820
2.908
2.991
3.188
3.208
3.294
3.512
3.607
3.693
3.809
3.928
3.989
4.103
4.217
4.288
4.495
4.634
4.686
4.784
4.962
4.987
5.064
5.324
5.288
5.404
6.070
5.695
5.633
8.125
6.008
5.815
8.125
6.337
5.969
8.125
6.862
6.045
8.125
7.282
6.093
8.125
7.526
6.131
8.125
7.625
6.178
8.125
7.705
6.237
8.125
7.786
6.295
8.125
7.861
6.349
8.125
7.928
6.380
8.125
7.965
6.399
8.125
7.988
6.488
8.125
8.042
6.494
8.125
8.092
6.539
8.125
8.125
6.580
8.125
8.125
6.624
8.125
8.125
6.636
8.125
8.125
Values listed under each gas type are in volts.
(V - 5)
V = log
(P) + 5
10
CO
KR
Freon12
2
1.000
1.000
1.000
1.301
1.301
1.301
1.699
1.523
1.699
2.028
1.668
2.125
2.355
1.970
2.487
2.672
2.370
2.883
3.012
2.675
3.172
3.345
2.979
3.473
3.741
3.372
3.863
4.033
3.671
4.157
4.325
3.963
4.445
4.696
4.341
4.798
4.982
4.614
5.044
5.249
4.865
5.250
5.550
5.141
5.447
5.743
5.309
5.556
5.886
5.433
5.621
6.002
5.514
5.680
6.065
5.548
5.751
6.157
5.606
5.851
6.253
5.654
5.918
6.353
5.679
5.962
6.448
5.710
5.996
6.532
5.734
6.025
6.611
5.754
6.050
6.658
5.765
6.063
6.687
5.772
6.072
6.766
5.787
6.092
6.847
5.799
6.111
6.936
5.812
6.128
7.028
5.822
6.146
7.140
5.828
6.164
7.169
5.830
6.169
VGC301 Controller
Freon22
D
Ne
2
1.000
1.000
1.000
1.301
1.301
1.301
1.699
1.699
1.699
2.125
2.080
1.903
2.487
2.392
2.166
2.855
2.778
2.551
3.136
3.082
2.849
3.434
3.385
3.150
3.837
3.779
3.543
4.136
4.082
3.844
4.424
4.393
4.148
4.783
4.828
4.553
5.037
5.174
4.867
5.255
5.579
5.192
5.471
7.288
5.696
5.602
8.125
6.252
5.675
8.125
7.608
5.722
8.125
8.125
5.780
8.125
8.125
5.877
8.125
8.125
5.950
8.125
8.125
6.000
8.125
8.125
6.038
8.125
8.125
6.070
8.125
8.125
6.097
8.125
8.125
6.112
8.125
8.125
6.122
8.125
8.125
6.146
8.125
8.125
6.167
8.125
8.125
6.187
8.125
8.125
6.204
8.125
8.125
6.222
8.125
8.125
6.228
8.125
8.125
(V - 5)
listed above
CH
4
1.000
1.301
1.699
2.167
2.523
2.893
3.186
3.484
3.886
4.197
4.500
4.893
5.201
5.517
5.877
6.374
7.409
7.930
8.125
8.125
8.125
8.125
8.125
8.125
8.125
8.125
8.125
8.125
8.125
8.125
8.125
8.125
8.125
Page 24
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