KROHNE BM 90 EN User Manual

Page 24

Pr. 52 Duty/Assist/Standby Pump Control (D=1)

Pr.53

Pump Exerciser (D=1)

Pr. 62 BM90E Serial Communication Enable (D=1)

Pr. 57 Pump Run-On Time (D=0)

Pr. 54 Pump Tolerance (D=1)

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 the pump running time in seconds.

(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.

Enter

All pumps in

drop out pump 3

drop out pump 1

drop out pump 4

drop out pump 2

drop out pump 5

To use this facility, first select alternating duty options 2 to

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-

cised in turn.

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.

N O T E:

a. The system assumes that the lower numbered

pumps turn on first.

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.

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.

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

cycle.

Pr. 56 Pump Run-On Interval (D=0)

Pr. 58 to Pr. 61 Unspecified

(Channel 1-RS232)

Channel 1 (RS232) 1 = Comminssioning System

(default)

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