KROHNE BM 26 A EN - Manual (Page 20)

20 Installation and Operating Instructions BM 26 A
1.6.4 Correcting the scale position to accurately read true liquid level
The scale* can be corrected by the customer using the following procedure:
Step Action
1
Find the float immersion depth “c” (supplied by KROHNE, refer also to section 1.6.3).
2 Subtract the dimension “a”, float base to magnet centreline (given on the float dimensioned
drawing in Section 1.6.2), from “c” to get the dimension “b”, scale correction factor.
Item Description
b = c – a (difference between liquid level
and indicator position due to product
density)
c = float immersion depth (a function of
product density), see section 1.6.3.
a = distance from centerline of magnet
system to the float base, see
dimensioned float drawings in
section 1.6.2.
1 = Float
2 = Follower magnet of indicator (or limit
switch)
3 = Position of magnets mounted in the
float
3 Loosen the two clamp collars holding the measuring scale onto the measuring tube using a
screwdriver or 8 mm wrench.
4 Bring the zero point (top of the lower red KROHNE plate) on the scale into line with the
centreline of the bottom lateral process connection.
4a Undo top collar
1 Measuring scale
2 Measuring tube
3 Top measuring scale collar
*This information also applies to the initial setting up of limit switches – however, the fitter should
also remember to take into account the limit switches offset trigger point (see section 3.6).