65
TN4FCXA2
j
-EDF-
E
Symptoms
Saturated
output current
(beyond 20mA)
Output current
Inexistant or
less than 3.8mA
Significant
error on current
output
Causes
1. Incorrect position of the by-pass valve
2. Process leakage
3. Problem with the piping
4. Plugged pipe
5. Error of the electrical supply and/or the
load resistance
6. The value of the supply voltage at the
transmitter terminals is incorrect
7. Defect of zero adjustment or the range
of measurement
8. Amplifier defect
1. Identical to causes 1 to 4 above
2. Inversion of polarity on the power
terminals
3. Defect of the electrical supply and/or the
load resistance.
4. The value of the power supply is
incorrect.
5. Amplifier defect
1. Bad connection of the mechanism
2. Mixture of liquid and gas
3.Variation of the density of the liquid.
4. Large change in the ambient
temperature
(5) zero drift and drift in the measurement
range.
6. amplifier defect
Solutions
Place the valve in the correct position.
Seal.
Check the pipes.
Unblock the pipes.
Checking the power supply and load
resistance values (refer to Sec. 7.2).
(For the intrinsic safety, the electrical voltage
is 16.1 to 26 Vdc)
Check the cable and the power supply as
shown above.
Adjust according to parag. 4
Replace the amplifier (see parag. 5.3)
Check the wiring (see parag. 7.1)
Checking of the power supply and load
resistance values (refer to Sec. 7.2).
(For the intrinsic safety, the electrical voltage
is 16.1 to 26 Vdc)
Check the cable and the power supply as
shown above.
Replace the amplifier (see parag. 5.3)
Modify the connections.
Bleed
Stabilise the density.
Reduce the ambient temperature
fluctuations to a minimum.
Readjust the zero and the range
Replace the amplifier according to parag. 5.3
