Pulsar dBi Series, Instruction Manual

Page: 55 / 65

Page47
P860 Sound Velocity
This option allows for the velocity of sound to be changed according to the
atmosphere the transducer is operating in. By
default the velocity is set for
342.72m/sec which is the speed of sound travelling in air at a temperature of
20
o
C .
The table below gives details of the velocity of sound in various gaseous
atmospheres In all cases the velocity indicated is that in a 100% gaseous
atmosphere at 0
o
C. In atmospheres less than 100% it may be necessary to
check the level indicated at near empty and near full and compare with the
actual level, several times, then adjust the
Sound Velocity accordingly to
obtain an accurately displayed reading.
Gas Sound Velocity
Chlorine 206 m/sec
Argon 308 m/sec
Oxygen 316 m/sec
Air 331.5 m/sec
Ammonia 415 m/sec
Methane 430 m/sec
Helium 435 m/sec
Neon 965 m/sec
P645 Vapour Temperature Compensation
The sound velocity in air increases or decreases at a uniform rate of
60cm/sec. per
o
C, however in atmospheres other than air it will change at a
different rate.
This option allows the rate of change in cm/sec. per
o
C to be set according to
the atmosphere and temperature present. The level indicated, should be
compared with the actual level, several times, then
Vapour Temperature
Compensation adjusted accordingly, to obtain an accurately displayed
reading. Default = 60 cm/sec. per
o
C