KROHNE BM 90 EN - Manual (Page 18)

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Pr. 7 Decimal Display (D=2)
3.5.2. Parameter definitions
The parameters define all the options that are available to
the operator of a Level-Sonic BM90. It may be easier to
read these in conjuction with the application examples on
pages 27 to 32.
Note : (D=) factory default entry for that parameter.
Enter
1 Liquid Level Measurement
2 Distance Measurement
3 Differential Level Measurement (DLD)
4 Open Channel Flow Metering (OCM)
Enter one of the following codes :
1 Feet
2 Metres To display in percent of
3 Inches span, set Pr. 40 to 1
4 Centimeters
The system will be set to work in the specified units but
the display can be made to display a percentage, a con-
verted value or a volume (Pr.40).
Pr. 1 Basic Application (D=2)
Pr. 2 Calibration / Display units (D=2)
Note : Any subsequent change of units in Pr.2 (i.e.
Pr.2 = 1-4) will reset parameters Pr.3 to Pr.6 to new
units and all other parameters will default to factory
resets.
Pr. 3 Empty Distance (D=10.00) / BM90L (D=15.00)
The distance from the face of transducer to the furthest
point away, usually the bottom of the container or chan-
nel. Enter the distance in the units selected in Pr.2.
NOTE:- We reccomend setting the unit to factory defaults
and let it measure the empty distance.
Enable Pr.37 if using temperature compensation.
Resolution is a function of this parameter.
The distance between the furthest and nearest points
over which measurement is required.
Enter distance in the units selected in Pr.2.
For differential applications, the value required is the
maximum difference in the levels to be measured.
Pr. 4 Operational Span (D=10.00) / BM90L (D=15.00)
Pr. 5 Blocking or blanking distance (D= 0.50)
The distance in front of the transducer, within which the
liquid should not enter and within which no return echoes
will be processed.
Enter in the units selected in Pr.2 (not %).
I M P O R T A N T : P L E A S E D O N O T R E D U C E T H E F A C T O R Y S E T
V A L U E WITHOUT R E F E R E N C E T O KROHNE S.A.
Pr. 6 Rate of Change (D=1.00)
This value should be as small as possible but greater
than the maximum rate of change of level. Do not
change this value unless you know that the rate of
change is greater than 1.0m/min or that the system con-
tinually ’tracks’ a level lower than the actual level.
If it is necessary to change the value, enter the new value
in units per minute selected in Pr.2. The suggested range
of values is 0.1 to 10 metres/min or the equivalent.
Relays
The 5 relays can be assigned to various functions
depending on the application, as shown below:
Hysteresis is fully adjustable, so for most functions it is
necessary to enter both "set" and "reset" values.
The relay state under normal operating conditions is
defined as:-
(e) = normally energised. De-energise when "set" value
is reached.
(d) = normally de-energised. Energise when "set" value
is reached.
"Failsafe" functions are detailed in Pr.23 - 27.
The relays can be programmed to give both high and low
alarm or control levels.
e.g. High alarm Set: 2.0m Low Alarm Reset: 0.5m
Reset: 1.8m Set: 0.2m
The system will automatically configure itself as high or
low alarm depending on which of the set and reset entries
has the higher value.
Note that on distance measurement only (Pr.1 = 2), the
highest value is furthest from the transducer.
Defaults are 0 for relay designations 8, 11, 14, 17 and 20.
Defaults are 0.00 for relay settings 9 & 10, 12 & 13, 15 &
16, 18 & 19, and 21 & 22.
The relays are controlled from parameters 8-22 as fol-
lows:
Relay 1 Relay 2 Relay 3 Relay 4 Relay 5
Designation Pr. 8 Pr.11 Pr.14 Pr.17 Pr.20
Set (l.e.d. on) Pr. 9 Pr.12 Pr.15 Pr.18 Pr.21
Reset (l.e.d. off) Pr.10 Pr.13 Pr.16 Pr.19 Pr.22
0 = No decimal places allowed.
1 = Up to 1 decimal place allowed.
2 = Up to 2 decimal places allowed.
3.= Up to 3 decimal places allowed