64
IM 767361-01E
Troubleshooting, Maintenance, and Inspection
Calibrating the Pressure Measurement Function
Calibration in this section means to establish the relationship between the values
displayed on the instrument and those shown on the standard equipment.
It is recommended that the instrument be calibrated every six months since it is
a high accuracy measuring instrument. When calibrating, close attention should
be paid to the pressure standard used and the measurement environment.
The pressure standard used for calibration of this instrument must provide
tracability to the national standard and have an accuracy of ±0.01% or higher.
If a piston pressure gauge is used as the standard, apply the correct pressure
to calibrate the instrument, with the following taken into account: gravity at the
measuring point, weight of the piston, correction to be made due to buoyancy in
the air, temperature coefficient, and measuring temperature.
Calibration and adjustment of the accuracy can be performed at YOKOGAWA.
Calibration and adjustment of the accuracy requires a high level of skill, so
contact your nearest YOKOGAWA representative as listed on the back cover of
this manual.
Calibrating the DMM Function (MT220 Only)
Calibration in this section means an adjustment of accuracy based on the
relationship between the values shown on the measuring instrument and those
shown on the standards instrument. Please note that it is up to the user to
calibrate the DMM function as YOKOGAWA does not perform this service.
Pressure Standards for Calibration
Digital multimeter:
DC voltage measuring accuracy ±6 ppm,
(YOKOGAWA model 1281 recommended)
Standard resistor (100 Ω):
Accuracy ±0.02%, (YOKOGAWA model 2794
recommended)
DC voltage/current generator: Stability ±0.02%, (YOKOGAWA model 7651
recommended)
Environment
Ambient temperature:
23±1°C
Corresponding humidity: 45 to 75%
Power supply voltage: 100 to 200/200 to 240 VAC, however you must use
the power cord supplied by YOKOGAWA with a 3-to-
2 prong adapter, and connect it to an outlet with a
protective ground terminal.
Frequency:
50±1 or 60±1 Hz
Vibration:
An amount that will have only negligible effect on the
instrument
Electric/magnetic fields: A distance from such fields so that they will not effect
the measured values
Surrounding area:
Amounts of gas from decomposing food, steam, salts,
and dust that will not effect the measured values.
Warm-up:
Before calibration, this instrument must be warmed
up for more than 30 minutes and earch standards
instrument must be warmed up for a time no shorter
than indicated by their specifications.
