SMAR LD290, Operation And Maintance Manual

Page: 35 / 66

Maintenance Procedure
4.3
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.
Pull the main board out of the housing and disconnect the power supply and the sensor connectors.
Reassembly Procedure
WARNING
Do not assemble with power on.
Sensor
When mounting the sensor ( 18 ), it is recommended to make use of a new set of gaskets ( 17 )
compatible with the process fluid.
O’rings should be lightly lubricated with silicone oil before they are fitted into their recesses. Use
halogen grease for inert fill applications.
The fitting of the sensor must be done with the main board out of the electronic housing. Mount the
sensor to the housing turning it clockwise until it stops. Tighten the screw (
8 ) to lock the body to the
sensor.
Electronic Circuit
Plug sensor connector and power supply connector to main board. If there is a display, attach it to the
main board by means of 4 screws (
3 ). The display can be installed in any of the 4 possible positions
(See Figure 4.2).
The”  ”
mark indicates up position.
Pass the screws (
5 ) through the main board holes ( 6 ) and the spacers ( 7 ) as shown on Figure 4.3 and
tighten them to the body.
Figure 4.2
– Four Possible Positions of the Display
After tightening the protective cover (
1 ), mounting procedure is complete. The transmitter is ready to be
energized and tested. It is recommended that adjustment be done on the ZERO TRIM and on the
UPPER PRESSURE TRIM.