KROHNE LEVEL-SONIC BM90 Series Installation And Operating Instructions Manual page 24

Pr. 52 Duty/Assist/Standby Pump Control (D=1)
Duty assist is where pumps are switched on by set point,
and kept on to assist earlier pumps. Duty standby is
where only one of the pumps specified for duty can be on
at a time, i.e. when the set point for the second pump is
reached and it switches on, the first pump will switch off.
Enter 1 - Duty/assist operation
2 - Duty/standby on pumps 1 and 2
3 - Duty/standby on pumps 1, 2 and 3
4 - Duty/standby on pumps 1, 2, 3 and 4
5 - Duty/standby on pumps 1, 2, 3, 4, and 5
The turn-off points for the pumps can all be the same, or
they can be different depending on the chosen "Set" and
"Reset" values for each relay.
Pr.53 Pump Exerciser (D=1)
T o u s e t h i s f a c i l i t y , f i r s t s e l e c t a l t e r n a t i n g d u t y o p t i o n s 2 t o
5 in Pr.51, depending on the number of pumps installed.
Enter the number of starts assigned to Pump 1 before the
sequence switches to allow the other pumps to be exer-
c i s e d i n t u r n .
Pr. 54 Pump Tolerance (D=1)
In applications where a greasy topped liquid is being
pumped, problems may occur due to build-up of grease
at the levels where pumping starts. It is usually neces-
sary for this to be cleared manually. To avoid this, vary-
ing the "turn on" point for the pumps by – 10% of the set
point value causes the build-up to occur over a larger
area, significantly reducing the maintenance problem.
Enter 1 - No tolerance applied to pumps
2 - Tolerance applied to all pumps
N O T E: The pump 'reset' points must be outside the toler-
ance band of the set points and blanking.
Pr. 55 Pump Maintenance Dropout (D=0)
The removal of one pump for maintenance can necessi-
tate a great deal of readjustment to ensure correct con-
trol. Pr.55 removes this need by allowing one pump to be
removed without affecting the control levels. Pumps are
re-assigned downwards so that the highest level is not
used, therefore, normal control levels are maintained for
lower level setting.
Enter
0 All pumps in
1 drop out pump 1
2 drop out pump 2
24
3 drop out pump 3
4 drop out pump 4
5 drop out pump 5
N O T E:
a. The system assumes that the lower numbered
pumps turn on first.
b .
CAUTION - A PUMP NOT INCLUDED IN AN
ALTERNATING SEQUENCE BUT PROGRAMMED INTO THE
FIXED PART OF THE SEQUENCE WILL BE SUBSTITUTED
INTO THE ALTERNATING SEQUENCE TO REPLACE A
PUMP DROPPED OUT.
c. This feature should not be used if the relays
are being used for a mixture of pump control and alarm
functions.
Pr. 56 Pump Run-On Interval (D=0)
When submersible pumps are used, it may be necessary
to pump down occasionally to clear the sludge from the
bottom of the well. This feature is controlled by Pr.56 and
Pr.57. Once in every interval defined by Pr.56, the pump
will run-on for the time period defined by Pr.57.
Enter the time interval in hours between each run-on
c y c l e .
Pr. 57 Pump Run-On Time (D=0)
Enter the pump running
(max. 120 seconds).
Only one run-on cycle occurs per interval as set by Pr.56.
Notes :
a) Caution is required when choosing a value for pump
run-on time, as extended pump run-on can lead to CAVI-
TATION, causing AIR LOCK or PUMP DAMAGE.
b) As overflow can occur, do not use pump run-on for
pump up operation, set Pr.56 and Pr.57 to zero.
c) Care should be taken if pump sequence and pump run-
on are defined together. As pump run-on will be assigned
to the last pump to turn off which could be any of those in
the sequence.
Pr. 58 to Pr. 61 Unspecified
Pr. 62 BM90E Serial Communication Enable (D=1)
(Channel 1-RS232)
Channel 1 (RS232) 1 = Comminssioning System
2 = Polled data transfer
Channel 2 (RS485) Is permanently enabled for polled
data transfer
Pr. 63 BM90E Station Number (D=0)
For plooed date transfer, the unit requires to have a sta-
tion number assigned to it in the range 1-31, which has to
be unique to the unit.
NOTE : Pr.62 & Pr.63 are not available on BM90LE
time in seconds.
( d e f a u l t )