Eurotherm 3116 PID Podręcznik Użytkownika Pobierz pdf (Strona 5)

7. TIMER OPERATION

A timer can be configured to operate in three different modes. These can be

selected in Level 2.

1. Dwell timer

2. Delayed switch on timer

3. Soft start timer

There are four operating states, all of which are available in Level 1:

Run may be initiated by pressing

and together.

Reset (of End State) when timer has timed out, may be initiated by pressing

and (Ack),

Reset, during timing, may be initiated by pressing and holding

and

(Note pressing Ack at this point does not reset the timer. The reason for this

is that if the display is on any view other than the HOME display then

pressing these two buttons will jump to HOME).

Hold may be initiated by pressing

and To run the timer from

hold, press quickly

and again

The above states may also be set by the following methods:-

• Edge trigger a suitably configured digital input

• Power cycle the controller

• Digital communications command

End cannot be set - it occurs automatically when the timer has counted

down to zero

Switching from Hold to Run through the front panel buttons is not allowable

if the Hold status is forced by a logic input or through Digital

Communications.

Timer operation is indicated by a beacon labelled RUN:

Timer Status RUN beacon

Reset Off

Run On

Hold Flashing

End Off

Logic outputs The timer may be configured to operate an output when it is

running or during the end state

Note:-

• Power up - the ‘run’ state is selected if a Soft Start or Delay

timer is configured or the ‘Reset’ state is selected if a Dwell timer

is configured.

• Auto/Manual is only available when the timer is in Reset

• Ramp Rate – it is recommended that ramp rate is used only with

a Dwell type timer

• Quick access to the timer operating parameters is available in

Level 2 by pressing

. Repeat pressing of this button shows

Timer Status, Dwell, Working Output, SP1, SP2, etc

7.1. Dwell Timer

A dwell timer (TI.CFG = DWELL) is used to control a process at a fixed

temperature for a defined period. The action which occurs at the end of the

timed period depends on the configuration of the END.T parameter.

Notes:

1. If THRES = 2

(for example) timer will show TIMER RUNNING with

the RUN beacon on but will not start counting down until the

temperature is, first, within 2

of SP. Then the threshold is ignored.

2. The DWELL period can be reduced or increased when the timer is

running. If it is reduced to meet the Time Elapsed the timer will

change to the End state.

3. A-M can only be selected when in reset

4. If the timer is re-configured to a different type or the End Type is re-

configured (a dwell, for example), it may be necessary to reselect Auto

mode

7.1.1. Simple Programmer

A four segment programmer is achieved using a dwell type timer with the set

point rate limit and threshold parameters set.

7.2. Delayed Switch On timer

The timer is used to switch on the output power after a set time.

When the timer status = run, the control output is off

When the timer status = reset, the control output is controlling at SP1

7.3. Soft Start Timer

The timer is used to start a process at reduced power and/or reduced

setpoint. Timing starts at power up or when ‘Run’ is selected.

When the Timer Status = Run, the controller power is limited by the soft

start power limit parameter. The Soft Start setpoint is a threshold which,

when exceeded, sets the timer to end. If the temperature is already above

this threshold when the timer is set to run, the timer will time out

immediately.

When the timer status = reset, the controller is controlling at SP1

TIMER END

OFF

End State end. t =

OFF SP2 dwel

SP2

Temp

SP1

Time

THRES

= + n

RUN Digital O/P = t.run

END Digital O/P = t.End

RESET

Digital Input

TIMER RUNNING

OFF

Scrolling

message

Counting

down

Temperature

RUN Digital O/P = t.run

Reset Run

RESET

Digital

input

SP1 (70)

Time

TIMER RUNNING TIMER END

Scrolling

Message

END Digital O/P = t.End

TIMER

RUNNING

TIMER

END

Timer soft start power limit

SS.PW R (40%)

Run

RESET

Digital input

Temp

Setpoint (70

Time

Output power High limit

Soft start setpoint

SS.SP (50

RUN Digital O/P = t.run

END Di

ital O/P = t.End

Reset

Scrolling

Message

Servo

to PV

start

THRES

= +

RESET

Digital

input

RUN Digital O/P = t.run

END Digital O/P = t.End

Temp

SP1

(

)

Time

SP2

(

)

Ramp to

SP1 at

SP.RAT

DWELL

Ramp to

SP2 at

SP.RAT

Counting down

TIMER RUNNING

TIMER

END

Scrolling

message

1 2 3 4 5 6

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