KROHNE LS 4100 EN - Manual (Page 16)

LS 4100/LS 4150 03/2002
16
5.2 Replacement of the electronics
The removal of the electronics unit will damage
the housing seal. Therefore only open the
instrument if you want to insert a new
electronics unit.
To replace the electronics in case of failure, the
instrument must not be removed. Proceed as
follows to replace the electronics unit:
•
Separate level switch from operating
voltage.
•
Loosen the plug (1), by screwing on the
knurled ring.
•
Loosen the plug insert (2) with a screw-
driver on the four slots (10) and pull it care-
fully out of the housing (6).
•
Remove the plug of the two connection
cables (7) from the socket on the board (8).
•
Grease (thin layer) the seal ring (4) of the
new plug insert with an acid-free grease.
•
Insert the connection cables (7) into socket
(8) on the board of the new oscillator.
•
Lower the plug insert (2) into the housing.
Make sure that the locking tab (3) is
approximately above the notch on the
housing edge (5).
•
Carefully push the plug insert (2) from
above into the housing (6). Push the four
snap-on hooks (9) with a screwdriver
inwards so that the plug insert can be more
easily inserted into the housing. Make sure
that the board does not get damaged.
•
Push the plug insert (2) flush to the housing
(6). Make sure that the locking tab (3)
snaps into the notch on the housing (5).
You can hear it when the snap-on hooks
(9) snap in the groove inside the housing. It
is not possible to loosen the parts without
damage.
•
Now screw the plug (1) back onto the
housing.
The level switch is again ready for use.
1 Plug
2 Plug insert
3 Locking tab
4 Seal ring
5 Notch
6 Housing
7 Connection plug
8 Socket
9 Snap-on hooks (4 pcs.)
10 Slots (4 pcs.)
Note that the switching point may change slightly because of the electronics replacement.
5.3 Maintenance
LS 4100/LS 4150 are maintenance-free.
Fig. 5.2