Page 168 
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. Default = 342.72m/sec 
P861 Cal. Dist 1 
When Ultra Wizard = 1 Level/Volume   
This  parameter  can  be  used  to  re-calibrate  the  Sound  Velocity  (P860), 
when the acoustic beam from the transducer is travelling through mediums 
other  than  air  or  when  there  are  variations  of  temperature  between  the 
transducer face and the material level.  
To obtain best results calibration should be carried out when the level is as 
near empty as possible and when any vapour present has stabilized.  
With  the  material  at  a  steady  level,  view  the  value  of  P861,  which  will 
indicate the current distance as calculated by Ultra 3 with respect to the 
current value of P860. Physically measure the distance from the face of the 
transducer  to  the  surface  of  the  material  level  and  enter  this  value,  in 
Measurement  Units  P104  and  P860  will  be  automatically  updated  to 
compensate for any difference between the displayed and entered values.