Hioki PW3336-01, Instruction Manual

Page: 42 / 206

2.5 Performing Zero-adjustment
36
Zero-adjustment (offset adjustment) is performed for voltage and current measured values after the instru-
ment has warmed up for approximately 30 minutes in order to ensure that its measurement accuracy specifi-
cations are satisfied. Zero-adjustment consists of degaussing (DEMAG) its internal current input unit and
performing offset adjustment for the voltage and current internal circuitry.
Although the zero-adjustment function operates automatically when the instrument is turned on, it should
always be performed before starting measurement after the instrument has warmed up.
Zero-adjustment adjusts offsets within the following ranges:
Voltage circuitry: ±10% of the measurement range
Current direct input circuitry: ±10% of the measurement range
External current sensor input circuitry: ±10% of the measurement range
Operating time: Approx. 40 sec. (No measured values are displayed during zero-adjustment.)
2.5 Performing Zero-adjustment
• Perform zero adjustment when there is no input to the instrument, for example after deactivating power to
measurement lines. If zero-adjustment is performed while there is input to the instrument, the process will
not complete normally, and you will be unable to make accurate measurements.
• Optional current sensors UNIVERSAL CLAMP ON CT 9277, 9278, and 9279 are not degaussed.
Degauss current sensors as described in the instruction manual that came with each current sensor
before performing the instrument’s zero-adjustment process.
• Zero-adjustment is performed for all channels, regardless of wiring mode or current input method.
• Settings cannot be changed, and integration cannot be started, during zero-adjustment.
• Zero-adjustment cannot be performed while integration is being performed or during display hold or maxi-
mum value/minimum value hold operation.
• To enable high-precision measurement, it is recommended to perform zero-adjustment at an ambient tem-
perature that falls within the range specified in the specifications.
• Perform the zero-adjustment process with no input. The instrument will display [ Err.18 ] if input is present
when performing zero-adjustment. If this occurs, remove the input and then repeat the zero-adjustment
process.
• It may be impossible to completely degauss the instrument’s current input unit if current input in excess of
the maximum input current is flowing to its current direct input terminals. In this case, perform zero-adjust-
ment multiple times or cycle the instrument’s power.
1
Deactivate power to measurement
lines and ensure that no input is
being supplied to the instrument.
2
Press to place the instrument in
the shift state and then press .
3
Zero-adjustment will be performed,
and the display will show [
- - - - -
] for
approximately 40 sec.
Once zero-adjustment is complete, the in-
strument will change to the normal mea-
sured value display and be ready for
measurement.