YOKOGAWA vigilantplant DM8, User Manual

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<5. MAINTENANCE>
5-2
IM 12T03A01-02E
5.2 Troubleshooting
Experiences are required for repair of the vibration type density meter; after parts are replaced,
adjustment may be necessary. If trouble occurs, as a rule, repair should be made by Yokogawa.
In this case, detailed information on abnormal phenomena will be effective for speedy recovery.
Searching method for abnormality is explained below. For the explosion-proof detector, confirm
that there are no explosive gases using a gas detector before removing the terminal box cover.
5.2.1 Checking the Vibrators
Remove the cover of the detector, so that the vibrator can be visually inspected.
Carefully check the entire surface of the two tubular vibrators. If they have dents, scratches,
holes or show signs of the sample liquid leakage, the vibrator assembly should be exchanged.
(CAUTION)
Make sure that the lock-screw is not in contact with the vibrator assembly.
CAUTION
The vibrator tube has extremely thin wall, hence must be carefully handled. Since assembling the
vibrator tube requires special skill, the exchange of the vibrator should be made by Yokogawa.
5.2.2 Checking the RTD
Measure electrical resistance between the terminal A2 and A3. When the RTD is normal, the
resistance shows the value indicated in the following table.
Table 5.1 Resistance at each temperature of RTD (Pt 1000Ω)
Temperature (°C) 10 15 20 25 30 35 40 45 50
Resistance (Ω) 1039.0 1058.5 1077.9 1097.3 1116.7 1136.1 1155.4 1174.7 1194.0
5th Edition : Dec. 11, 2015-00