Honeywell SC1000 Manual Do Utilizador

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SC Series Instruction Manual     page 113
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12
12.6.4 
CALIBRATION TYPE
 
Menu Item
This chooses the type of calibration technique to be used. There are two methods
that can be used to calibrate the transducer to the Input Channel.  Each has
advantages and disadvantages as described in the table below.
It is important to know your application in order to select the appropriate cali-
bration type.  When the best possible accuracy is required, Known-Load Calibra-
tion is recommended.  However, if known-loads are not available, Shunt
Calibration may be used instead. 
The choices for this menu item are:
TYPE= SHUNT CAL
” means Shunt Calibration.  First, you are prompted to apply 
the load entered in the “
ZERO SCALE VALUE
” register. Next, the instrument inter-
connects the Shunt Cal 1 and Shunt Cal 2 pins.  This activates the trans-
ducer’s or in-line amplifier’s shunt calibration circuit which causes a 
predictable apparent signal. The instrument then takes a reading and adjusts 
itself using the “
SHUNT CAL VALUE
” register.
TYPE= 2 POINT CAL
” means 2-Point Known Load Calibration.  You are prompted 
to apply the loads to the transducer that were entered in the “
KNOWN POINT 1/2
” 
and “
KNOWN POINT 2/2
” registers.  This technique assumes that the transducer is 
linear, so the usual loads used are zero scale and full scale.
TYPE= 3 POINT CAL
” means 3-Point Known Load Calibration.  You are prompted 
to apply the loads to the transducer that were entered in the “
KNOWN POINT 1/3
” 
and “
KNOWN POINT 2/3
” and “
KNOWN POINT 3/3
” registers.  This technique can be 
Table 1-7: Comparison of Calibration Types
Shunt Calibration
2-, 3-, or 5-point 
Known Load 
Calibration
RECOMMENDED...
...for most applications
no
yes
...when frequently swapping 
transducers
yes
no
...when best possible accuracy 
required
no
yes
PROS and CONS
Relative accuracy
good
best
Requires actual, calibrated loads 
to be applied
no
yes
CALIBRATION TECHNIQUE
Zero-scale point from...
applied load
applied load
Full-scale point from... 
transducer output 
when Shunt Cal pins 
connected
applied load
Linearity correction from...
N/A
2-point: none
3- or 5-point:
applied load