Hioki LR8450 - Page 37

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Conguring Input Channels
Thermocouple wire break detection
• The system checks for wire breaks by applying a minuscule current at the date refresh intervals
when measuring temperature using thermocouples.
• Measured values are not a󰀨ected since wire breaks are detected when measurement is not being
performed.
• If the data refresh intervals are the same, setting [Burn out] to [ON] will result in less e󰀨ective
noise rejection since it results in a cuto󰀨 frequency that is higher than the [OFF] setting.
Check “Digital lter” of each module in “10.2 Plug-in Module Specications” (p. 310) for the cuto󰀨
frequency.
• If the thermocouple resistance exceeds roughly the next value, the system will determine that a
wire break has occurred.
Thermocouple
Range
100°C f.s. 500°C f.s. 2000°C f.s.
K 260
Ω
5400
Ω
2940
Ω
J 470
Ω
4150
Ω
200
Ω
E 1530
Ω
5970
Ω
9290
Ω
T 220
Ω
5440
Ω
5440
Ω
N 520
Ω
1470
Ω
590
Ω
R 50
Ω
40
Ω
890
Ω
S 50
Ω
80
Ω
1300
Ω
B – – 2090
Ω
C 220
Ω
910
Ω
3090
Ω
When using a long thermocouple with [Burn out] set to [ON], use a thick-diameter wire to avoid false wire
break detection.
HIOKI LR8450A964-03
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information@itm.com1.800.561.8187