KROHNE CORIMASS G-MFM 4085 EEx EN - Manual (Page 6)

6
After opening the converter housing as described above, one of the following operations may
be performed by the local KROHNE service engineer :-
• Replace supply fuse F9
• Changing electronics
• Changing supply voltage setting
• Changing EPROM’s
These operations are to be performed in an identical manner to the standard converter.
(Please refer to the standard operation manual).
Make sure the correct main fuse (right value, ceramic body, 1500A) and the corresponding fuse
label on the fuse housing is used. Fuses and labels may be ordered from KROHNE.
Using wrong fuses violates the Ex approval and may damage the system.
The earthing metal sheet of the electronic must be fastened firmly with the srew onto the
converter housing!
The converter should be ‘high pot’ tested according to a specific procedure. Therefore, it is not
permitted to change output modules or any other hardware components (except the list
mentioned above by the local service engineer) without repeating the ‘high pot’ test. Please
contact KROHNE for advice.
1.3
Installation of the MFM 4085 K EEx and MFM 4085 F EEx
In order to get the highest possible accuracy, the user is advised to carry out the pipework
installation as described in the standard manual.
Further requirements / differences are listed below :
• The ideal installation factor of an E E x unit is much higher than of a standard system. The
high installation factor does not mean less accuracy. Due to Zener barriers and clamping
diodes the E
E x system consumes more power during running.
The installation factor should have a value as indicated in the following table.
Meter Size Installation factor
10 G
100 G
300 G
800 G
1500 G
3000 G
200
150
400
300
300
400
The correct operation of the Zener barriers inside the converter are only guaranteed with a
ridged and safe connection of the converter housing with potential earth (potential
compensation PA). Please use the outer earthing connector at the square flange of the
converter housing for earthing.
In case the converter housing has a pressure tight termination compartment, make sure the
connected cable glands / adapters have an Ex certification.