ULTRA 4 INSTRUCTION MANUAL 
 
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P854 Fixed Temperature 
This parameter sets the temperature, in degrees centigrade to be used if 
P852 (Temperature Source) =3.  Default = 20
o
C. 
Velocity 
P860 Sound Velocity 
This parameter 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 sound travelling in air at an ambient temperature of 20 degrees 
centigrade (at 1bar, atmospheric pressure).  Default = 342.72 m/sec.