Unipulse F805AT-BC, Operation Manual

Page: 180 / 202

11.TROUBLESHOOTING
165
11-9. Calibration Error
CAL. ERR 1
Re-calibration of zero point is required.
Normally, a zero calibration is followed by a span calibration. If the span calibration
produces unsatisfactory results, F805AT-BC shows the error message (CAL.ERR.1),
indicating that a re-calibration of zero is necessary. Satisfactory re-calibration of zero
will remove the error message.
CAL. ERR 2
Subtracted value for initial dead load exceeds
the F805AT-BC’s allowable zero-calibration
range. Check if an unwanted load is being
applied to the load cell. If the error message
still appears in normal measuring conditions,
zero point re-calibration must be done after
shifting zero point by connecting a resister
across the load cell’s +EXC and –SIG terminals.
The table below summarizes the relation between the resister value and input signal.
The values shown in the table apply to a 350 Ω load cell. Parallel connection of four
load cells reduce sensitivity to one-fourth of that of single load cell: the resister value
should be reduced accordingly (to 1/4).
Temperature coefficient of the resister directly affects the reading accuracy. Use
resisters with temperature coefficient less than 50ppm/
℃
(5ppm/
℃
recommended).
Resistance Equivalent strain at input
Calculated Approx. μ -STRAIN mV/V
875 K Ω
437 K Ω
291 K Ω
219 K Ω
175 K Ω
146 K Ω
125 K Ω
109 K Ω
97 K Ω
87.3 K Ω
79.4 K Ω
72.7 K Ω
67.1 K Ω
62.3 K Ω
58.2 K Ω
54.5 K Ω
51.3 K Ω
48.4 K Ω
45.9 K Ω
43.6 K Ω
41.5 K Ω
39.6 K Ω
37.9 K Ω
36.3 K Ω
34.8 K Ω
866 K Ω
442 K Ω
294 K Ω
221 K Ω
174 K Ω
147 K Ω
124 K Ω
110 K Ω
97.6 K Ω
86.6 K Ω
78.7 K Ω
73.2 K Ω
66.5 K Ω
61.9 K Ω
57.6 K Ω
54.9 K Ω
51.1 K Ω
48.7 K Ω
46.4 K Ω
43.2 K Ω
41.2 K Ω
39.2 K Ω
38.3 K Ω
36.5 K Ω
34.8 K Ω
200
400
600
800
1000
1200
1400
1600
1800
2000
2200
2400
2600
2800
3000
3200
3400
3600
3800
4000
4200
4400
4600
4800
5000
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2.0
2.1
2.2
2.3
2.4
2.5
Connect a
+EXC
+SIG
-EXC
-SIG
resister between
+EXC and -SIG