Pump Control - Brainchild BTC-2500 User Manual

4 12 Pump Control

4 12 Pump Control
Pump Control function is one of the unique features of BTC-2500. Using this Pump Control function is one of the unique features of BTC-2500. Using this
function the pressure in a process can be controlled excellently. The pressure function the pressure in a process can be controlled excellently. The pressure
in a process is commonly generated by a pump driven by a variable speed in a process is commonly generated by a pump driven by a variable speed
motor. The complete system has the following motor. The complete system has the following
control behavior: , The system is very noisy. , The pressure is changed very control behavior: , The system is very noisy. , The pressure is changed very 1 1
rapidly. , The pump characteristics is ultra nonlinear with respect to its speed. rapidly. , The pump characteristics is ultra nonlinear with respect to its speed. 3 3
4 4 , The pump can't generate any more pressure as its speed is lower than half , The pump can't generate any more pressure as its speed is lower than half
of its rating speed. , An ordinary pump may slowly lose the pressure even if of its rating speed. , An ordinary pump may slowly lose the pressure even if 5 5
the valves are completely closed. the valves are completely closed.
Obviously a conventional controller can't fulfill the conditions mentioned above. Obviously a conventional controller can't fulfill the conditions mentioned above.
Only the superior noise rejection capability in addition to the fast sampling rate Only the superior noise rejection capability in addition to the fast sampling rate
owned by BTC-2500 can realize such application. To achieve this, set the owned by BTC-2500 can realize such application. To achieve this, set the
following parameters in the setup menu: following parameters in the setup menu:
FUNC=FULL FUNC=FULL
EIFN=NONE EIFN=NONE
PVMD=PV1 PVMD=PV1
FILT=0.5 FILT=0.5
SELF=NONE SELF=NONE
SPMD=PUMP SPMD=PUMP
SP2F=DEVI SP2F=DEVI
and program the following parameters in the user menu: and program the following parameters in the user menu:
REFC= Reference constant REFC= Reference constant
SP2= A negative value is added to SP1 to obtain the set point for idle SP2= A negative value is added to SP1 to obtain the set point for idle
state state
Since the pump can't produce any more pressure at lower speed, the pump Since the pump can't produce any more pressure at lower speed, the pump
may not stop running even if the pressure has reached the set point. If this may not stop running even if the pressure has reached the set point. If this
happens, the pump will be over worn out and waste additional power. To avoid happens, the pump will be over worn out and waste additional power. To avoid
this, the BTC-2500 provides a this, the BTC-2500 provides a
PUMP is selected for SPMD, the controller will periodically test the process by PUMP is selected for SPMD, the controller will periodically test the process by
using this reference constant after the pressure has reached its set point. using this reference constant after the pressure has reached its set point.
test shows that the pressure is still consumed by the process, the controller test shows that the pressure is still consumed by the process, the controller
will continue to supply appropriate power to the pump. will continue to supply appropriate power to the pump.
the pressure is not consumed by the process, the controller will gradually the pressure is not consumed by the process, the controller will gradually
decrease the power to the pump until the pump stops running. As this decrease the power to the pump until the pump stops running. As this
happens, the controller enters happens, the controller enters
point which is obtained by adding SP2 to SP1 until the pressure falls below point which is obtained by adding SP2 to SP1 until the pressure falls below
this set point. The idle state is provided for the purpose of preventing the this set point. The idle state is provided for the purpose of preventing the
pump from been restarted too frequently. The value of SP2 should be pump from been restarted too frequently. The value of SP2 should be
to ensure a correct function. to ensure a correct function.
The pump functions are summarized as follows: The pump functions are summarized as follows:
1. If the process is demanding material ( ie. lose pressure ), the controller 1. If the process is demanding material ( ie. lose pressure ), the controller
will precisely control the pressure at set point. will precisely control the pressure at set point.
2. If the process no longer consumes material, the controller will shut off the 2. If the process no longer consumes material, the controller will shut off the
pump as long as possible. pump as long as possible.
3. The controller will restart the pump to control the pressure at set point as 3. The controller will restart the pump to control the pressure at set point as
soon as the material is demanded again while the pressure falls below a soon as the material is demanded again while the pressure falls below a
predetermined value ( ie. SP1+SP2 ). predetermined value ( ie. SP1+SP2 ).
80
characteristics characteristics
2 2
Reference Constant REFC Reference Constant REFC
idle state idle state . The idle state will use a lower set . The idle state will use a lower set
UM25001C
which affects the which affects the
in the user menu. If in the user menu. If
If the If the
If the test shows that If the test shows that
negative negative
PUMP: A Cost Effective PUMP: A Cost Effective
yet Perfect Solution yet Perfect Solution
Key menu Key menu
SPMD SPMD
SP2F SP2F
REFC REFC
SP2 SP2
Pump Control Features: Pump Control Features:
1. Minimum oscillation of pressure 1. Minimum oscillation of pressure
2. Rapidly stabilized 2. Rapidly stabilized
3. Guaranteed pump stop 3. Guaranteed pump stop
4. Programmable pump stopping 4. Programmable pump stopping
interval interval