LD301 - Operation and Maintenance Instruction Manual
5.4
NOTE
A 21.0 or 3.6 mA current indicates that the transmitter is in Burnout (TRM) or safety output (PID).
Use the configurator to investigate the source of the problem.
Symptom: DISPLAY INDICATES "FAIL SENS"
Probable Source of Trouble:
Sensor Connection to the Main Board
Check the connection (flat cable, male and female connectors).
Type of Sensor Connected to the Main Board
Check if the sensor connected to the main board is the one specified for the LD301 model:
Sensor type shall be hyper - High Performance.
Electronic Circuit Failure
Check if the sensor set is damaged, replacing it for a spare one.
Disassembly Procedure
WARNING
Do not disassemble with power on.
Figure 5.1 shows a transmitter exploded view and will help you to visualize the following:
Sensor
In order to have access to the sensor (27) for cleaning purposes, the transmitter should be removed
from its process connections. The transmitter should be isolated from the process by means of
manifolds or valves; then, the drain (23) must be opened to vent any remaining pressure.
After this, the transmitter may be removed from the standpipe. The flange bolts (18) may now be
loosened, one at a time. After removing bolts and flanges (17), the isolating diaphragms will be easily
accessible for cleaning.
Cleaning should be done carefully in order to avoid damaging the delicate isolating diaphragms. Use of
a soft cloth and a nonacid solution is recommended.
To remove the sensor from the electronic housing, the electrical connections (in the field terminal side)
and the main board connector must be disconnected.
Loosen the hex screw (8) and carefully unscrew the electronic housing from the sensor, observing if the
flat cable is not excessively twisted.
WARNING
To avoid damage do not rotate the electronic housing more than 270º starting from the fully threaded
without disconnecting the electronic circuit from the sensor and from the power supply. See Figure 5.2.
Electronic Circuit
To remove the circuit board (6), loosen the two screws (5), that anchor the board and hold the (7)
spacers in the other side to avoid losing them.
WARNING
The board has CMOS components, which may be damaged by electrostatic discharges. Observe
correct procedures for handling CMOS components. It is also recommended to store the circuit
boards in electrostatic-proof cases.
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