KROHNE BM 70 A Installation And Operating Instructions Manual page 53

8.6.16 Tank type, movement of product surface
For optimum results, data acquisition and evaluation must
bematched to typical tank characteristics: movement of
the product surface, rapid or slow changes in the product
level, agitators, etc.
Fct. 3.5.9 TANKTYPE
•
STORAGE T.
Storage tank, still surface, slow
rate of change in level
•
PROC.TANK
Process tank, slight surface movement, rapid rate of
change in level
•
AGITATOR (for BM 70 A only)
Process tank with agitator, turbulent product surface
It is normally not critical if the tank type is set one step
out. However, "AGITATOR" should not be set for a storage
tank, and "STORAGE T." should not be set when an
agitator is fitted.
It is possible, for instance, that the measured value will
change in small steps rather than linearly or will "freeze" at
times when the setting is grossly incorrect.
Installation and operating instructions BM 70 A/P
8.6.17 Switching output
The functions for the switching output can be applied to:
a) the additional switching output in the Version "Ex-e or
Ex-i current output HART
b) the current output if Fct. 3.3.1 FUNCTION I is set to
"SW.OUTP.".
Fct. 3.6.1. FUNCTION S
Use this function to select the measured variable.
•
OFF (= deactivated; Fct. 3.6.2, 3.6.3 and 3.6.4 are no
longer selectable, i.e. they are skipped over).
•
LEVEL
•
DISTANCE
•
CONVERSION
•
REFLECTION
•
ERROR OPEN (default)
•
ERROR CLOSED
(Explanatory notes: see Table overleaf)
Fct. 3.6.2. TYPE S
•
This function is not shown (is skipped over) when OFF
or ERROR OPEN or ERROR CLOSED is set under
Fct. 3.6.1. Not significant is this case!
•
Use this function to set the type of switching output:
HIGH (= contact closes when upper limit of threshold
+ hysteresis / 2) exceeded
LOW (= contact closes when lower limit of threshold -
hysteresis / 2) exceeded.
Fct. 3.6.3 THRESHOLD
•
This function is not shown (is skipped over) when OFF,
ERROR OPEN or ERROR CLOSED is set under Fct.
3.6.1. Not significant in this case!
•
Use this function to define the threshold (limit value).
•
Setting of LEVEL or DISTANCE under Fct. 3.6.1:
Unit same as for Fct. 3.1.1 TANKHEIGHT. If a refe-
rence or tank bottom offset is set, this must be taken
into consideration!
•
Setting: CONVERSION under Fct. 3.6.1:
Unit same as in Fct. 3.2.3 UNIT.CONV.
•
Setting: REFLECTION under Fct. 3.6.1:
Setting range : 0...100.
Fct. 3.6.4 HYSTERESIS
•
This function is not shown (is skipped over) when OFF,
ERROR OPEN or ERROR CLOSED is set under Fct.
3.6.1. Not significant in this case!
•
Use this function to define the hysteresis.
•
Setting: LEVEL or DISTANCE under Fct. 3.6.1:
Setting range and unit same as for Fct. 3.1.1
TANKHEIGHT.
•
Setting CONVERSION under Fct. 3.6.1:
Unit same as in Fct. 3.2.3 UNIT.CONV.
•
Setting REFLECTION under Fct. 3.6.1:
Setting range: 0...100.
Examples of application and setting
see Sect. 8.5
Page: 53
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