Hioki Memory HiLogger LR8401-20 Instruction Manual page 282

20
A
Appendix 9 Frequently Asked Questions
Question
How to minimize thermocouple
measurement error when moving
the HiLogger between places with
much different temperatures?
When connecting a thermocouple
directly to the HiLogger, should
reference junction compensation
be set to external (EXT) or internal
(INT)? How is accuracy affected?
How to display only CH1 to CH3?
I want to measure motor tempera-
ture. How can I display the differ-
ence between ambient
measured temperature in real
time?
How can I acquire maximum, min-
imum, and average values every
hour?
I am measuring humidity with a
converter that converts 0 to 100%
RH to 1 to 5 V. How can I read hu-
midity directly?
Remedial Action
For thermocouple measurements, ter-
minal temperature is measured by an in-
ternal sensor to provide reference
junction compensation. When the ambi-
ent temperature changes abruptly, or
when air blows directly on the terminals,
errors occur due to thermal imbalance
between the terminals and temperature
sensor. When the HiLogger is moved to
a location with significantly different am-
bient temperature, allow at least 60 min-
utes for thermal equalization before
measuring.
Select INT when connecting a thermo-
couple (or compensating leads) directly
to the HiLogger. Overall measurement
accuracy is the sum of the accuracies of
the thermocouple and the reference
junction compensation (RJC).
Example: when measuring 0 to 100°C
with a K 100°C f.s. thermocouple
For ±0.6°C thermocouple accuracy and
±0.5°C RJC accuracy, temperature
measurement accuracy is ±1.1°C.
Select only the channels to be used on
the Input Channel Settings display. To
acquire data without displaying it, select
× as the waveform display color.
Use the waveform calculation function.
Calculates and displays the waveform
of the real-time sum, difference, prod-
and
uct, or quotient of values measured on
two channels.
"Interval Calculation" calculates and dis-
plays the latest results after each inter-
val.
TXT format data can be saved to remov-
able storage in real time.
Set the scaling method to [2-pt], and en-
ter the values.
(1:1 conversion → 0, 2:5 conversion →
100, units: %RH)
Reference page
"Instrument Installation"
(p .6)
"Temperature Mea-
surement Settings (us-
ing thermocouples)" (p
.58)
"Input Channel Set-
tings" (p .55)
"Selecting Waveform
Display Color" (p .67)
"8.3 Waveform Calcu-
lations" (p. 161)
"8.1 Calculate Aver-
age, Maximum, Mini-
mum, and Etc." (p. 155)
"3.6 Scaling Settings
(as needed)" (p. 71)