KROHNE OPTIFLUX 4040 C Ex EN - Manual (Page 17)

MAINTENANCE AND SERVICE
5
17
OPTIFLUX 4040 C
www.krohne.com 09/2010 - 7312232100 - AD EX OPTIFLUX 4040 C R01 en
5.1 Maintenance
The flowmeters are maintenance free with respect to the flowmetering properties. Within the
scope of periodic inspections required for electrical equipment installed in hazardous areas it is
recommended to check the housing for signs of damage or corrosion. This concerns the
converter housing and the flow sensor housing.
5.2 Replacement of electronics unit
Before opening:
• Make absolutely sure that there is no explosion hazard!
• Gas-free certificate!
• Make sure that all connecting cables are safely isolated from all external sources!
When these instructions are strictly followed, the display cover (with the glass window) can be
removed.
Removal of the electronics unit
• Raise the latch of the interlocking device by loosening the hexagon socket head cap screw
size 3, until the cover can rotate freely.
• Unscrew the cover with the special plastic wrench that is supplied with the device.
• Unscrew the two screws of the display unit and turn it carefully aside.
• Carefully disconnect the 12 pin connector (for field coil and electrode circuits connection)
from the electronics unit.
• Unscrew the two mounting screws of the electronics unit, which fixes the metal frame to the
back of the signal converter housing. A crosshead screwdriver type 2 Pt. Philips is most
suitable.
• Carefully remove the electronics unit of the converter housing. Do not damage any
connecting cables!
Insertion of the electronics unit
• Insert the electronics unit in the converter housing
• Tighten the two mounting screws of the electronics unit.
• The metal frame of the electronics unit must be securely screwed to the housing (back-end of
electronics compartment) by the two non-removable fastening screws. Screw them with a
tightening torque of 1.3 Nm.
• Connect the 12-pin connector.
• Mount the display-unit.
• Before the cover is screwed back into the housing, the screw-thread must be clean and well
greased with an acid and resin-free grease, e.g. silicone grease.
WARNING!
the following instructions must always be carefully followed, if the housing of the signal
converter has to be opened respectively closed again.
WARNING!
These two screw connections also establish the safety-technical connection of the electronics
unit to the signal converter housing and equipotential bonding system.