Bronkhorst E-7000 - Manual (Page 37)

BRONKHORST HIGH-TECH B.V.
9.17.004 page 37
3.11.4 Presentation of parameters
Parameters 'a - d' and 'e - h' are polynomial function parameters, which can be obtained with a mathematical
program out of measured calibration points.
All parameters will be printed on the calibration certificate.
They will be presented in scientific notation with 5 significant digits, where the last digit is obtained by
rounding-off.
Example (unscaled):
a = -2.7458 · 10
-3
e = -2.5396 · 10
-4
b = +9.5452 · 10
-1
f = +1.0892
c = -1.2714 · 10
-1
g = +1.7832 · 10
-2
d = +1.8464 · 10
-1
h = -1.1417 · 10
-1
Polynomial function for sensor signal:
Y = -2.7458 · 10
-3
+ 9.5452 · 10
-1
· X - 1.2714 · 10
-1
· X
2
+ 1.8464 · 10
-1
· X
3
Polynomial function for setpoint:
Z = -2.5396 · 10
-4
+ 1.0892 · Y + 1.7832 · 10
-2
· Y
2
- 1.1417 · 10
-1
· Y
3
3.11.5 Using polynomial functions at readout/control unit
The parameters for the polynomial functions are stored at the readout and control-module and can be
changed from the keyboard.
Normally both transfer functions of sensor signal and setpoint are linear Y = X, the transfer function of the
setpoint signals is Z = Y.
The connected device will have linearized transfer functions after (normal) calibration.
The accuracy however, will be
≤
1 % full scale.
When a special polynomial function calibration is wanted, the parameters 'a-h' will be destillated and printed
on the calibration certificate. In the 'INSTRUMENT'-menu you just have to enter these values.
Now you can connect and operate the concerned device.
Note:
Only this device will operate correctly; if you want to connect an other device to this channel, first change the
polynomial function parameters.