Sintrol S303 - 8.4.11 Integer Display Intercept a

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8.4.11 Parameter 11: Display Intercept “a” (Integer) -99...099 [mg/m3]
The instrument can be set to show mg/m
3
by utilizing a linear regression line which has an equation of the
form y = a + bx.
Parameter 11, 12, 13 and 14 will NOT change the actual mA-output signal.
These parameters are used to show mg/m
3
on the local display according to the defined linear
regression curve
The following glossary is based on the terminology used in the European stack testing regulations.
AMS Automatic Measurement System
(in this case Sintrol S304)
SRM Standard Reference Method
(usually Gravimetric Sampling)
y Result of SRM [mg/m
3
]
a The Intercept [mg/ m
3
] (Par. 11,12)
b The Slope [mg/ m
3
/mA] (Par. 13,14)
x Result of AMS [mA]
Example calculation:
yi [mg/m3]
xi [mA]
Comment
Point 1
6,00
9,00
(In a simple one-point calibration 4 mA would equal 0 mg/m3)
Point 2
19,00
17,00
(Result of the gravimetric sampling)
1. Calculate the slope b by the two-point form of a straight line
b = y
2
-y
1
/x
2
-x
1
In our case: b = 19,00-6,00 / 17,00-9,00 = 1,625
2. Resolve the equation y
i
= a + b x
i
to the intercept a
a = y
i
- b x
i
3. Calculate the intercept a by inserting x and y of either of the points
a = y
1
- bx
1
In our case: a = 6,00 – 1,625*9,00 = -8,625
Figure 18Example for display calibration
The values for the intercept a and the slope b are split into an integer and decimal part.
To change the integer part of the intercept a, follow the below procedure:
 Navigate to Parameter 11 by pressing K1
 Key the calculated value into the instrument -99...099 [mg/m3], default = 0 [mg/m3]
 Safe the result by pressing K3