Recorder; Analog Mode - LEYBOLD GRAPHIX ONE Instruction Manual

7.6

Recorder

The chart recorder output is a programmable analogue output. The voltage at the chart
recorder output is a function of the pressure at the sensor. The relationship between
pressure and voltage is termed output characteristic. It may be selected through the
parameter Analogue mode.
7.6.1

Analog Mode

Through the parameter Analog Mode you can define at which pressure value the maximum
voltage shall be reached. In the following, the available output characteristics are described.
Here information is provided in each case how the pressure p (in mbar) is calculated from
the output voltage U (in Volt).
Note here that a difference is made between a logarithmic and linear output characteristic.
Using a logarithmic characteristic is preferred when the measurement range extends over
many decades of pressure. In this case, the pressure value is logarithmized and thereafter
scaled suitably. Using a linear characteristic is preferred when the measurement range
extends only over a few pressure decades. In this case, the voltage at the chart recorder
output is proportional to the pressure value.
Log
Logarithmic representation of the entire measurement range.
TTR
TTR100
ITR
PTR
PTR90
CTR
DU
Table 37 – Chart recorder output – Calculation formula for the parameter Log
Log A
Logarithmic representation of the entire measurement range (compatible to A-series).
TTR
TTR100
ITR90
ITR200
PTR
PTR90
CTR
DU
Table 38 – Chart recorder output – Calculation formula for the parameter Log A
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Sensor
Sensor
Pressure [mbar]
p = 10^[U/(10/7) – 4]
p = 10^[U/(10/7) – 4]
p = 10^[U/(10/12) – 9]
p = 10^[U/(10/7) – 9]
p = 10^[U/(10/12) – 9]
p = 10^[U/(10/4) – 4] * FS
p = 10^[U/(10/4) – 4] * FS
Pressure [mbar]
p = 10^[U/(10/6) – 3]
p = 10^[U/(10/7) – 4]
p = 10^[(U – 7.75)/0.75]
p = 10^[U – 8]
p = 10^[U/(9/7) – 9 – 7/9]
p = 10^[U/(10/11) – 8]
p = 10^[U/(10/4) – 4] * FS
p = 10^[U/(10/4) – 4] * FS
GA300550402_002_C1 – 10/2016