Hioki LR8450, Instruction Manual

Page: 27 / 310

23
Configuring Input Channels
Unit Measure Channel Trigger Alarm Calculation System
Thermocouple wire break detection
• The system checks for wire breaks by applying a minuscule current each date refresh interval
when measuring temperature using thermocouples.
• Measured values are not affected 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 effective
noise rejection since it results in a cutoff frequency that is higher than the
[OFF]
setting.
Check “Digital filter” of each module in “10.2 Plug-in Module Specifications” (p. 243) for the cutoff
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.
1
Settings and Operation