TECO F33 Series, Instruction Manual, Page: 111 / 192

108 Functional Description
Lower Band Limit [39C]
If the speed of the pump reaches the lower band limit,
the 'top' pump is stopped immediately without delay. If
a stop delay is used this delay will be ignored. Range is
from 0%, equalling min speed, to the set percentage for
the Lower Band [398].
Communication information
Fig. 94 Lower band limit
Settle Time Start [39D]
The settle start allows the process to settle after a
pump is switched on before the pump control contin-
ues. If an additional pump is started D.O.L. (Direct On
Line) or Y/
,
the flow or pressure can still fluctuate
due to the 'rough' start/stop method. This could cause
unnecessary starting and stopping of additional
pumps.
During the Settle start:
• PID controller is off.
•
The speed is kept at a fixed level after adding a
pump.
Communication information
Transition Speed Start [39E]
The transition speed start is used to minimize a flow/
pressure overshoot when adding another pump. When
an additional pump needs to be switched on, the mas-
ter pump will slow down to the set transition speed
start value, before the additional pump is started. The
setting depends on the dynamics of both the master
drive and the additional drives.
The transition speed is best set by trial and error.
In general:
• If the additional pump has 'slow' start/stop dynam-
ics, then a higher transition speed should be used.
•
If the additional pump has 'fast' start/stop dynam-
ics, then a lower transition speed should be used.
Communication information
Example
Max Speed = 1500 rpm
Min Speed = 200 rpm
TransS Start = 60%
When an additional pump is needed, the speed will be
controlled down to min speed + (60% x (1500 rpm -
200 rpm)) = 200 rpm + 780 rpm = 980 rpm. When this
speed is reached, the additional pump with the lowest
run time hours will be switched on.
Default: 0%
Range:
0 to Lower Band level. 0% (=min speed) means
that he Limit function is switched off.
Modbus Instance no/DeviceNet no: 43172
Profibus slot/index 169/76
Fieldbus format Long, 1=1%
Modbus format EInt
Default: 0 s
Range: 0-999 s
A
39C Low Band Lim
Stp 0%
(NG_50-PC-15_2)
Speed
Max
Min
Lower band
Stop Delay [39A]
Lower band
limit [39C]
“top” pump stops
immediately
Flow/Pressure
Δ
A
39D Settle Start
Stp 0s
Modbus Instance no/DeviceNet no: 43173
Profibus slot/index 169/77
Fieldbus format Long, 1=1 s
Modbus format EInt
Default: 60%
Range: 0-100% of total min speed to max speed
Modbus Instance no/DeviceNet no: 43174
Profibus slot/index 169/78
Fieldbus format Long, 1=1%
Modbus format EInt
39E TransS Start
Stp 60%
A