11-5
Chapter 11.  CALIBRATION
Current Transformer (CT) input calibration
(1)  Select the [CT input calibration] tab.
(2)  Select a desired channel to be calibrated.
(3)  Select [Zero] from the zero span selection items. 
(When selecting a channel, perform the [Zero] calibration first, and then 
perform the [Span] calibration next since “Zero/Span” is set for one channel.)
(4)  Click [Read].
(5)  A current value of “0” is applied to the CT input terminal of the channel you 
have selected and keep the apply status for approximately 30 s. For details 
about how to connect measuring instruments in the apply status, refer to the 
following Figures: 
Current
generator
CT input 1
This unit
-
+
(7)
(8)
(9)
Current
generator
CT input 2
This unit
-
+
(7)
(8)
(9)
(6)  Click [Write].
(7)  Select [Span] from the zero span selection items.
(8)  Click [Read].
(9)  Apply a span current value to the CT input terminal of the channel you have 
selected and keep the apply status for approximately 30 s.
(10) Click [Write].
(11) If any channels to be calibrated remain, return to operation step (2).
 
 Handling Precautions
To calibrate the CT input, connect the DC current (mA) to the input 
terminal.