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4–12 Pump Control

Pump control function is one of the

unique features of the TEC-9300.

Using this function, the pressure in

a process can be excellently con-

trolled. The pressure in a process is commonly generated by a

pump driven by a variable speed motor. The complete system has

the following characteristics which affect control behavior. 1. The

system is very noisy. 2. The pressure changes very rapidly. 3. The

pump characteristics are ultra nonlinear with respect to its speed.

4. The pump can’t generate any more pressure if its speed is lower

than half of its rating speed. 5. An ordinary pump may slowly lose

pressure even if the valves are completely closed.

Obviously, a conventional controller can’t fulfill the conditions

mentioned above. Only the superior noise rejection capability in

addition to the fast sampling rate possessed by the TEC-9300 can

handle such an application. To achieve this, set the following

parameters in the setup menu:

FUNC = FULL

EIFN = NONE

PVMD = PV1

FILT = 0.5

SELF = NONE

SPMD = PUMP

SP2F = DEVI

and program the following parameters in the user menu:

REFC = reference constant

SP2 = a negative value added to SP1 to obtain the set point for

the idle state

Since the pump can’t produce

any more pressure at lower

speeds, the pump may not

stop running even if the pres-

sure has reached the set point.

If this happens, the pump will

be overly worn and waste

additional power. To avoid

this, the TEC-9300 provides a

reference constant REFC in

the user menu. If 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. If the test shows that the

pressure is still consumed by the process, the controller will con-

tinue to supply appropriate power to the pump. If the test shows

that the pressure is not consumed by the process, the controller

will gradually decrease the power to the pump until the pump

stops running. When this happens, the controller enters an idle

state. The idle state will use a lower set 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 pump

from been restarted too frequently. The value of SP2 should be

negative to ensure that the controller functions correctly.

The pump functions are summarized as follows:

1. If the process is demanding material (i.e., loses pressure), the

controller will precisely control the pressure at the set point.

2. If the process no longer consumes material, the controller will

shut off the pump for as long as possible.

3. The controller will restart the pump to control the pressure at

the set point as soon as the material is demanded again while

the pressure falls below a predetermined value (i.e., SP1+SP2).

Programming guide:

1. Perform auto-tuning to the system under such conditions that

the material (i.e., pressure) is exhausted at typical rate. A typi-

cal value for PB1 is about 10Kg/cm≈, TI1 is about 1 second,

TD1 is about 0.2 seconds.

2. If the process oscillates around the set point after auto-tuning,

then increase PB1 until the process can be stabilized at the set

point. The typical value of PB1 is about half to two times the

range of the pressure sensor.

3. Increasing FILT (filter) can further reduce the oscillation

amplitude. But a value of FILT higher than 5 (seconds) is not

recommended. A typical value for FILT is 0.5 or 1.

4. Close the valves and observe whether the controller can shut

off the pump each time. The value of REFC should be adjust-

ed as little as possible so that the controller can shut off the

pump each time when all the valves are closed. A typical value

for REFC is between 3 and 5.

5. An ordinary pump may slowly lose pressure even if the valves

are completely closed. Adjust SP2 according to the rule that a

more negative value of SP2 will allow the pump to be shut off

for a longer time when the valves are closed. A typical value

for SP2 is about -0.50Kg/cm≈.

An example for pump control is given in section 5-1.

4–13 Remote Lockout

The parameters can be locked to prevent them from being

changed by using either hard-

ware lockout (see section 1-3),

remote lockout, or both. If you

need the parameters to be

locked by using an external

switch (remote lockout func-

tion), then connect a switch to

terminals 13 and 14 (see sec-

tion 2-10), and choose LOCK for EIFN (see section 4-1).

If remote lockout is configured, all parameters will be locked

when the external switch is closed. When the switch is left open,

the lockout condition is determined by internal DIP switch (hard-

ware lockout, see section 1-3).

Hardware lockout: Can be used only during initial setup.

Remote lockout: Can be used any time.

Key menu

SPMD

SP2F

REFC

SP2

PUMP:

A cost effective solution

Pump control features:

1. Minimum oscillation of

pressure

2. Rapidly stabilized

3. Guaranteed pump stop

4. Programmable pump stop-

ping interval

Remote Lockout:

1. Connect external switch

to terminal and .

2. Set LOCK for EIFN

3. Lock all parameters

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