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18.
Scale calibration
18.1 Scale calibration
To maintain the measurement accuracy, it is recommended to calibrate this recorder every year.
Calibration name
Description
Zero/span
adjustment
Execute the adjustment by inputting the zero and span of each
measurement range.
* As for this recorder, the AD converter and one KR31*1 every four
channels do the input process to KR31*0 with one AD converter every
twelve channels.
Therefore, KR31*1 inputs and adjusts zero and the span of each cooking
stove of each input terminal unit of each input terminal unit three times
once to KR31*0.
* The sensor correction (shift of value) for each channel can also be performed.
（
Refer to 13.2
Input operation settings.
）
18.2 Calibration environment
Items
Reference conditions
Ambient temperature
23°C±2°C
Ambient humidity
50%±10%
Power voltage
100VAC±
１
%
Power frequency
50Hz or 60Hz±0.5%
18.3 Preparation
18.3.1 Preparation of tools
Input types
Tools
DC
voltage
Thermocouple
Resistance
thermometer
Remarks
DC voltage current
generator
Accuracy: Better than ±0.05%
Reference junction
compensator
0°C±0.2°C
Thermocouple for
test
Same type of thermocouple
as the input
Standard variable
resistor
Accuracy: Better than ±0.05%
３
-core copper wire
Same resistance value per
core
18.3.2 Before calibration
(1) Attach the terminal board cover and turn the power on.
(2) Take the warm-up time for more than 30 minutes until this recorder stabilizes. (The ideal warm-up
period is more than 1 hour.)
The check and adjustment of measured values need careful cautions for the adjustment work
besides tools such as standard tools and reference conditions.
When the check and adjustment of measured values are required, contact your local CHINO’s sales
agent.
About adjustment
Remarks
18
