Unipulse F159, Operation Manual

Page: 54 / 126

4.CALIBRATION
45
Calibration Error 2
Initial dead load exceeds the zero adjustable range of the F159. Check if the cell
is loaded with any extra object.
If the
Calibration Error 2 persists while the system is loaded correctly, Zero
calibration must be performed again after inserting a resistor bEXC and
–SIG terminals of the load cell for shifting zero point. The relation between input
signal shift and resistor values are summarized in the table below.
・
The values contained in the table assume single 350
Ω
load cell configuration.
・
Temperature coefficient of the resistor directly affect reading accuracy. Use
resistor with temperature coefficient better than 50ppm/
℃
(5ppm/
℃
class
recommended)
Resistor Voltage shift equivalent strain
Calculated
Approximate
value
μ
-STRAIN mV/V
875 K Ω 866 K Ω 200 0.1
437 K
Ω
442 K
Ω
400 0.2
291 K Ω 294 K Ω 600 0.3
219 K
Ω
221 K
Ω
800 0.4
175 K Ω 174 K Ω 1000 0.5
146 K Ω 147 K Ω 1200 0.6
125 K
Ω
124 K
Ω
1400 0.7
109 K Ω 110 K Ω 1600 0.8
97 K
Ω
97.6 K
Ω
1800 0.9
87.3 K Ω 86.6 K Ω 2000 1.0
79.4 K Ω 78.7 K Ω 2200 1.1
72.7 K
Ω
73.2 K
Ω
2400 1.2
67.1 K Ω 66.5 K Ω 2600 1.3
62.3 K
Ω
61.9 K
Ω
2800 1.4
58.2 K Ω 57.6 K Ω 3000 1.5
54.5 K Ω 54.9 K Ω 3200 1.6
51.3 K Ω 51.1 K Ω 3400 1.7
48.4 K Ω 48.7 K Ω 3600 1.8
45.9 K
Ω
46.4 K
Ω
3800 1.9
43.6 K Ω 43.2 K Ω 4000 2.0
41.5 K
Ω
41.2 K
Ω
4200 2.1
39.6 K Ω 39.2 K Ω 4400 2.2
37.9 K Ω 38.3 K Ω 4600 2.3
36.3 K
Ω
36.5 K
Ω
4800 2.4
34.8 K Ω 34.8 K Ω 5000 2.5
Insert a resistor
+EXC
+SIG
-EXC
-SIG
bEXC and –SIG.