KROHNE BM 90 EN - Manual (Page 38)

38
A PPENDIX 1 Vessel or Flume
linearisation
This feature allows volume conversion to be applied on
irregular shaped vessels and flow measurements to be
made on open channels providing that level/volume/flow
relationships are known.
The system allows the entry of a volume or flow profile of
up to 16 points into memory, that is then used to pro-
duce the required flow or volume values when in ‘RUN‘
mode. The required profile is stored in parameter 35.
Before proceeding it is useful to write down the point
numbers and ’A’/’b’ values to facilitate programming.
Note l % Head or Level designated ’A’
l % Flow or Volume designated ’b’
Flow
When using the facility for flow it is enabled by Pr.40 = 4.
The profile is stored as percentage of head, against per-
centage of flow.
Volume
When using the facility for volume, it is enabled by
Pr.32 = 8. The profile is stored as percentage of level,
against percentage of the total volume.
Procedure
The procedure uses a 16 point curve to map the profile,
but all 16 points do not have to be used.
The profile data is input into Pr.35 which when accessed
[Pr.35, ‘DSP‘, ‘ENT‘] will display ‘A1‘, which means the
data pointer is at value 1 on ‘A‘ data. The values can be
displayed and changed as required.
% Flow or Volume
Designated ’b’
% Head or Level
Designated A
Pr.44 - Keyboard Controls
#
Toggles the display between data blocks ‘A‘
and ‘b‘
s Increases and decreases the point number,
t when either the point number or its value is
displayed
C E Clears the display when inputting a new value.
D S P Toggles the display between the block and
point number and the value.
E N T Enters a new value.
TEST Exits Pr.44 and returns the operator to the
normal program.
0-9 The number keys and decimal point are used
to input new values. Point numbers can only be
changed by using the ‘ s ‘ and ‘ t ‘ keys.
Pr.44 - Inputting Values
When a new value is to be entered, first display the old
value and then input the new and press ‘ENT
‘ ,
the sys-
tem will display the value it has stored in memory. The
values input have to be in a specific form.
1. Head or Level designated ‘A ‘
These values must be a whole number. Decimal places
will be ignored.
i.e. 11 will be accepted as 11
22.3 will be accepted as 223.
The allowable range of values is 0-250 %, any unused
data values must be set to 255.
P A R A M E T E R R E S E T L O A D S 255 T O ALL D A T A V A L U E S
2. Flow or Volume designated ‘b‘
These values are expected to contain one decimal place,
therefore, it is not necessary to input the decimal place,
but the procedure will display it.
i.e. 10 will be accepted as 1.0
100 or 10.0 will be accepted as 10.0
The allowable range of values is 0-500 %
P A R A M E T E R R E S E T L O A D S 0 T O ALL D A T A V A L U E S .
Note :
1. As time is required to enter all the data, the standard
keypad timeouts are suspended.
2. We recommend that the required values are written in
table form, as shown, before programming commences.
Then enter all Block A values, before entering all block b
values.