Pressure Systems 9816 Manuale Utente

Pressure Systems, Inc.                                                                              98RK-1 & 9816 User’s Manual© 
 
 

 

Page 100 

 

www.PressureSystems.com 

 

 

 
Each individual DH200 transducer within the NetScanner

 System Intelligent Pressure 

Scanner contains nonvolatile read/write memory capable of storing the transducer’s full thermal 
and pressure calibration data.  The internal firmware of each module reads all of these 
calibration data from each transducer upon power up and then dynamically calculates 
conversion coefficients that convert transducer output into pressure at the current measured 
temperature.  The firmware uses these coefficients for all subsequent engineering-unit data 
conversions performed. 
 
All NetScanner

 System Intelligent Pressure Scanner modules use a third-order polynomial to 

convert transducer output voltage to pressure.  All calculations are carried out internally using 
high precision math.  The following formula is used for all pressure output calculations. 
 
 

P

T

(V)  

= 

[C

0

(T) + C

1

(T)*V + C

2

(T)*V

2

 + C

3

(T)*V

3

] * C 

SPAN

 + C

RZ

 

  where: 
 

P

T

 

 

= 

Calculated applied pressure 

 V 

  = Transducer 

output 

voltage 

 

C

0

(T) .. C

3

(T)  =    Conversion coefficients generated from calibration data at 

 temperature 

T. 

 

C

RZ

 

 

= 

Re-zero adjustment’s “offset" correction coefficient 

 

C

SPAN 

 

= 

Span adjustment’s “gain” correction coefficient 

 
Since the polynomial’s coefficients are a function of the current temperature, they are 
dynamically re-calculated by the module firmware (with other equations) to compensate for each 
transducer’s measured temperature change. 
 
Each model 9816 Intelligent Pressure Scanner contains an integral purge/leak check calibration 
manifold. Through software commands to each 9816, this valve may be placed in one of four 
positions:  RUN, CAL, PURGE, or LEAK-CHARGE.  (See the  Set/Do Operating 
Options/Functions (‘w’) command (ii=0C & 12) in Chapter 3, and in particular the Valve 
Position Chart at the end of command’s description.)  The 98RK-1 contains pneumatic 
backplane inputs for CAL (CAL 1-8) and CAL REF.  When each module’s internal calibration 
valve is placed in the CAL/RE-ZERO position (through software commands), all DH200 
transducer  pressure inputs are pneumatically connected to the CAL input ports.  All DH200 
reference inputs are pneumatically connected to the CAL REF input port.  The CAL input may 
be used to perform on-line zero adjustment of the transducers.  This capability virtually 
eliminates sensor zero drift error and ensures the highest possible data accuracy.  The CAL 
input may also be used for DH200 span adjustment calibrations.  Span calibration of multi-range 
scanners may also utilize the CAL 1-8 ports if the highest applied pressure does not exceed the 
proof pressure rating of any installed transducer.