USER'S GUIDE____________________________________________________________________  
78 __________________________________________________________________ M210855EN-D 
DPMAX 
The serial line command DPMAX shows or sets the maximum 
permissible difference pressure allowed between barometer modules. 
The command is only available if more than one barometer module 
has been installed. 
DPMAX [x] [y] [?] 
where: 
x = Pressure 
y = Unit 
 
Example: 
>dpmax 0.2 
Max. diff.     : 0.20 hPa 
> 
 
If the defined value is exceeded, the relevant digits in the ERR field 
(see FORM command) change from 0 to 1, and the corresponding 
pressure measurement(s) are no longer included in the average 
pressure reading. 
Vaisala recommends using the ERR field as part of the 
FORM 
command definition if there are two or three pressure transducers in a 
PTB330 series digital barometer.  
The following basic cases may occur for barometers with two or three 
pressure transducers (only the differences found between the readings 
from the pressure transducers are important): 
          P high     
      P high     
  ≤ DPMAX ? 
Two transducers: ≤ DPMAX ?  Three transducers:      P middle    
 
      P low    
  ≤ DPMAX ? 
          P low    
 
 
For an acceptable measurement crucial conditions are:  
-  two transducers: P high - P low 
 DPMAX 
- three transducers: 
P high - P middle 
 DPMAX and P middle - P low  DPMAX. 
The factory setting for DPMAX is 1 hPa.