IFM LT80 Series, Operating Instructions Manual

Page: 36 / 41

36
13.5 Calculation aids [OP]
For proper functioning of the overflow prevention OP a minimum
distance (y) (Fig. 12-1) must be observed (→ 6.1) .
The following applies (Fig. 12-1):
B + c = L + u
and
B = z + y
B: tank height L: probe length
c: outside length (maximal (→ 6) u: distance between probe and tank
bottom
y: required response level OP
from the cover (minimum
→ 6.3 , maximum → 13.4 ).
z: required response level OP from
the bottom (maximum: z < L - c - y
or z < B - y).
13.5.1 Definition "from the cover“
Requested distance (y) of the overflow prevention OP
"from the cover“ is defined.
• Without offset ([OFS] = [0]): [OP] = L - c - y
• With offset ([OFS] = u): [OP] = L - c - y + u
or
[OP] = B - y
Example LT8022:
c = 3.0 cm, y = 5.0 cm, u = 1.0 cm
Without offset: [OP] = 26.4 cm - 3.0 cm - 5.0 cm
= 18.4 cm
With offset: [OP] = 26.4 cm - 3.0 cm - 5.0 cm + 1.0 cm
= 19.4 cm
Fig. 12-1
OP
c
z
B
L
13.5.2 Definition "from the bottom“
Response
level (z) of the overflow prevention OP from the tank bottom is defined.
• Without offset ([OFS] = [0]): [OP] = z - u
• With offset ([OFS] = u): [OP] = z
Example LT8022:
z = 18.0 cm (from the tank bottom), u = 1.0 cm
Without offset: [OP] = 18.0 cm - 1.0 cm = 17.0 cm
With offset: [OP] = 18.0 cm
Round the calculated value to the next lower adjustable value → 13.4 .