Measurement Specialties 9116 User Manual

Pressure Systems, Inc.                                                                                        Model 9116 User’s Manual 
 
 

 

Page 63 

 

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CALCULATE AND SET OFFSETS  (Command ‘h’) 
 

Instructs a module to calculate new offset coefficients with zero differential  

  pressure 

(or 

a 

specified “generated” pressure) applied to the specified channels.   

 

 

These new coefficients update part of the module’s internal calibration coefficient  

 

 

database, used to convert any subsequent raw data into engineering units data.   

 

 

The  new offset values are also returned in the response. This command is  

 

 

sometimes called a Re-zero or zero-only calibration. 

 

“hpppp [vv.vvvv]” 
 
‘h’  is the command letter 
‘pppp’ is the  position field 
‘vv.vvvv’ is an [optional] applied pressure value preceded by a space 
character 

“g.gggg .. [g.gggg]...” 
 
‘g.gggg’ are the actual offset data values returned, each preceded by a  
space. 

 
 
Description:  The  position field may have 0 or 4 characters.  If no position field is specified,  
 

 

  offset coefficients for all of a module’s input channels will be calculated and  

 

 

  returned.  If a  position field is specified, offset coefficients for only the channels  

 

 

  whose bits are set (=1) will be calculated and returned. If the optional pressure  

  

 

value 

[ 

vv.vvvv] is specified, the position field must be 4 characters, even when  

 

 

  all channels are to be specified.  If the optional pressure value [‘vv.vvv’] is not  

 

 

  provided, an applied pressure of 0.0 psi(a) will be assumed when calculating  

 

 

  coefficients. Offset values are returned in the response in order of highest  

channel to lowest specified channel, with data formatted per an implied  

 

 

  decimal format (f=0). 

 

  Before acquiring data with this command, any addressed Model 9116 module  
 will 

normally attempt to place the calibration valve in the CAL position, so that a  

  zero differential pressure can be applied to all channels via the module’s CAL  
  and CAL Ref input port.  Simply leaving these ports unattached will allow the  
  transducers to read the appropriate zero differential pressure if ambient air  
  pressure is stable.  After data are acquired, the calibration valve will be placed in  
  the RUN position.  To disable the automatic shifting of the calibration valve, refer  
 to 

the 

Set Operating Options (‘w’) command (index 0B).  The reader is also  

 referred 

to 

Section 4.2 of Chapter 4 for additional details concerning the  

  performance of a Re-zero Calibration.