Instruction Manual

IM 01C21F01-01E
9-2
9. MAINTENANCE
Table 9.2.1 Instruments Required for Calibration
Name RemarksYokogawa-recommended Instrument
Power
supply
Model SDBT or SDBS distributor
Load
resistor
Model 2792 standard resistor [250 Ω ±0.005%, 3 W]
Load adjustment resistor [100 Ω ±1%, 1 W]
Voltmeter
Model 2501 A digital multimeter
Accuracy (10V DC range): ±(0.002% of rdg + 1 dgt)
Digital
manometer
Model MT220 precision digital manometer
1) For 10 kPa class
Accuracy: ±(0.015% of rdg + 0.015% of F.S.)
±(0.2% of rdg + 0.1% of F.S.)
2) For 130 kPa class
Accuracy: ±0.02% of rdg
±5digits
±(0.2% of rdg + 0.1% of F.S.)
3) For 700 kPa class
Accuracy: ±(0.02% of rdg + 3digits)
±5 digits
±(0.2% of rdg + 0.1% of F.S.)
4) For 3000 kPa class
Accuracy: ±(0.02% of rdg + 10 digits)
±(0.2% of rdg + 0.1% of F.S.)
5) For 130 kPa abs class
Accuracy: ±(0.03% of rdg + 6 digits)
4 to 20 mA DC signal
Select a manometer having
a pressure range close to
that of the transmitter.
Pressure
generator
Model 7674 pneumatic pressure standard for 200 kPa {2 kgf/cm
2
}, 25 kPa {2500 mmH
2
O}
Accuracy: ±0.05% of F.S.
Requires air pressure
supply.
Pressure
source
Model 6919 pressure regulator (pressure pump)
Pressure range: 0 to 133 kPa {1000 mmHg}
Prepare the vacuum pump
for negative pressure
ranges.
Dead weight gauge tester 25 kPa {2500mmH
2
O}
Accuracy: ±0.03% of setting
Select the one having a
pressure range close to
that of the transmitter.
T0901.EPS
for 0 to 10 kPa
for -10 to 0 kPa
for 25 to 130 kPa
for 0 to 25 kPa
for -80 to 0 kPa
for 100 to 700 kPa
for 0 to 100 kPa
for -80 to 0 kPa
for 0 to 3000 kPa
for -80 to 0 kPa
for 0 to 130 kPa abs
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Note: The above table contains the instruments capable of performing calibration to the 0.2% level. Since special maintenance and management
procedures involving traceability of each instrument to higher-level standards are required for calibration to the 0.1% level, there are
difficulties in calibration to this level in the field. For calibration to the 0.1% level, contact Yokogawa representatives from which the
instrument was purchased or the nearest Yokogawa office.
P
If a pressure generator
is used:
Reference pressure
Supply pressure
Model 7674 pneumatic
pressure standards
V
RRc
Load resistance,
250 Ω
Load
adjustment
resistance,
100 Ω
Digital voltmeter
Power
supply
E
If a pressure source and
a manometer are combined:
Model MT220
precision digital manometer
F0901.EPS
Reference pressure
Pressure source
V
RRc
Load resistance,
250 Ω
Load
adjustment
resistance,
100 Ω
Digital voltmeter
Power
supply
E
P
Figure 9.3.1 Instrument Connections