Hioki Memory HiLogger LR8401-20 Instruction Manual page 71

About Burn-Out Detection
• When burn-out detection (Burn Out) is enabled (On), a tiny sensing current is applied during each
recording interval during thermocouple measurements to detect broken wires.
• Detection current is timed to avoid affecting measured values.
• For a specific recording interval, the filter cut-off frequency is higher when burn-out detection is
enabled, so noise suppression is less effective.
"Chapter 11 Specifications": "Cut-off frequency" (p .239)
See:
• When measuring the temperature of the range's +f.s., the wire is considered to be broken when
the thermocouple resistance exceeds nearly following values. When burn-out detection is en-
abled with extended thermocouple wires, be sure that the wire diameter is sufficient.
K
J
E
T
Thermocouple N
R
S
B
W
For example, measurement in the 100
wire extended beyond about 20 meters is detected as a burn-out.
If Thermocouple Measurement Range is Exceeded, or
when a measured value far exceeds the range limit
(range label)
• Example: Using a type T thermocouple with range -200 to +400°C
When a measured value exceeds the measurement range of the
thermocouple and far exceeds the range limit (range label), the
waveform saturates at the top of the screen, as shown at the right.
• When a measured value far exceeds range limit (range label),
"OVER" or "-OVER" is displayed in place of numerical/cursor val-
ues, and the following values are applied to calculations and data
storage.
Input type Input range
100°C
Thermocouple
500°C
(Tc)
2000°C
• With burn-out detection enabled, burn-out is detected when mea-
surement input exceeds the range of the thermocouple, and far
exceeds the selected measurement range.
Range
100°Cf.s. 500°Cf.s.
260 5400
470 4150
1520 7400
220 5440
520 1470
90 40
90 80
− −
220 910
°
C range with a K-type thermocouple and 0.32 mm diameter
+OVER value
327.67
1638.4
3276.7
3.3 Input Channel Settings
2000°Cf.s.
4370
1630
390
5440
590
880
1300
2090
3090
Unit: Ω
°
[ C]
1000
400
0
-200
-1000
-OVER value
-327.68
-1638.4
-3276.8
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