9-4
9-4 Calibration
Calibration is done every channel, in principle. Even if the same range is set, an error may occur between
channels to be exact.
1. Preparation
①
Turn off the power switch and connect cables according to input signals. (See the following figure)
Connect the input terminals of this unit to a channel to be calibrated.
②
Mount the terminal cover.
③
Turn on the power switch and select one-point sequential display mode.
④
Display the channel to be calibrated.
⑤
After 30 minutes or longer, start calibration.
2. Calibration method
①
Set the tester (DC standard voltage generator or precise variable resistor) to an input value equivalent to
the scale to be calibrated.
②
Read the digital indicating value to check if the error is within the specified accuracy.
③
Change the channel to be calibrated next, and observe the same procedure.
④
Check the analog indication and dotting positions, too.
(Caution 1) Accuracy of tester
The basic accuracy of this unit is ±0.05%. Accordingly, the calibration does not mean any more unless a
tester having the higher accuracy is used. Be careful with a thermocouple error. Be careful since the
tester must be stabilized sufficiently before use for securing its accuracy and stability.
(Caution 2) Reference junction temperature compensator
Make sure that the reference junction temperature is 0
℃
. If an electronic reference junction temperature is
used, refer to its instruction manual for connections, etc. Be careful with the compensation accuracy.
(Caution 3) If no reference junction temperature compensator (RJ) is available
Adopt [connection1] if RJ selection is set to [Int] in thermocouple input and no reference junction
temperature compensator is available. In this case, set the RJ selector to [Ext] during calibration only.
In this case, the reference junction temperature compensation errors cannot be calibrated.
(Caution 1)
The accuracy of this unit is specified at 23
℃
±2
℃
. Secure the safety of the surrounding
environment.
(Caution 2)
If the unit is adjusted by the shift adjustment function of measured values, take the deviation
into account correspondingly.
(Caution 3)
When connections were changed after removing the cover, mount the terminal cover, and
then, continue applying power for longer than 30 minutes before starting the calibration work.
Connection 1
(DC voltage input)
Connection 2
(Thermocouple input)
Connection 3
(Resistance thermometer bulb input)
Use three copper conductor wires
each having the same length and
same size.
Precise
variable resistor
This unit
Input terminals
Copper con-
ductor wire
Output terminals
Copper con-
ductor wire
Input terminals
Output terminals
This unit
DC standard
voltage generator
Reference junction
(0
℃
)
Reference junction temperature compensator
Thermocouple
Thermocouple
Copper con-
ductor wire
Input terminals
Output terminals
This unit
DC standard
voltage generator
