Logix
®
420 Digital Positioner FCD LGENIM0106-07-AQ – 10/15
30
13 MAINTENANCE AND REPAIR
The kits listed in section 15.2 SPARE PARTS KITS can be replaced by a
technician trained in positioner function and handling of static sensitive
devices.
1
CAUTION: Depressurize the positioner before servicing.
1
CAUTION: Use eye protection.
1
CAUTION: When touching the circuit boards, observe
precautions for handling electrostatically sensitive devices.
13.1 Scheduled Maintenance
The supply gas filter(s) should be scheduled for regular maintenance
as required to maintain supply gas quality. If contamination is found
in the filter, the inside of the positioner should be visually inspected
for contamination. If contamination is found in the positioner, the
positioner should be replaced.
13.2 Required Tools and Equipment
The Logix 420 digital positioner has modular components that can be
replaced using these tools:
13.3 Replacing a Main Board
Removal
1. Make sure the valve is bypassed or in a safe condition.
2. Remove the outer cover.
3. Disconnect the power to the positioner.
4. Remove the inner cover by removing the 3 retaining screws.
5. Gently lift the main board rotating the bottom up while keeping the
top in place.
6. Disconnect the hall sensor cable, the piezo cable and the feedback
cable. Use a small flat screwdriver to press in the locking features
and carefully separate the connector from the main board. Be
careful not to pull the cable, as this may cause damage to the cable.
Installation
1. Place the main board on the positioner base with the 4-20 mA input
on the same side as the electronic access ports.
2. Lift the main board rotating the bottom (configuration switches)
upwards while keeping the top in place.
3. Connect the piezo cable, the hall sensor cable, and the feedback
cable. Ensure the connector’s locking features engage.
4. Place the main board on the positioner base, ensuring the cables
are clear of the feedback gears.
5. Replace the inner cover by inserting the 6 retaining screws.
6. Calibrate.
Figure 15: Tools for Positioner Maintenance
Figure 16: Main Board Connectors
Philips Screwdriver #2
Philips Screwdriver #1
Flat Screwdriver
Piezo
Connector
Hall
Sensor
Connector
Feedback
Pot
Connector
2.5 mm Hex Driver