gefran 3850T Use And Installation Manual page 114

7. EXAMPLES AND APPLICATION NOTES
There are two ways of approaching the setpoint:
• Non impulsive behaviour
For non impulsive behaviour, set T_HI T_OF = 0 and T_
OF = 0: each request greater than T_LO is continuously
sent to the actuator on OPEN/CLOSE outputs.
The minimum duration of the pulse is settable in T_ON
as a percentage of the actuator time, you should set
T_ON = T_LO.
With power equal to 100.0% or 0.0%, the correspond-
ing output remains active.
• Impulsive behaviour
- T_HI ≠ 0 and T_OF = 0
For impulsive behaviour, set T_HI ≠ 0 and T_OF = 0:
each request greater than T_LO is sent to the actu-
ator on OPEN/CLOSE outputs with T_ON duration
pulses. The Off time of the impulses will become
longer in proportion as we approach the position to
be reached.
T_HI defines the deviation within which switching
becomes impulsive.
Example with T_HI 20.0%
or deviation of 15% to 75% will be:
- from 15 to 55 continual
- from 55 to 75 with amplitude impulses T_ON
(T_OFF cannot be set as parameter T_HI is
already in use and will create conflict)
With power equal to 100.0% or 0.0%, the corre-
sponding output remains active.
- T_HI = 0 and T_OF ≠ 0
T_HI = 0 and T_OF ≠ 0: any request greater than T_
LO is sent to the actuator via OPEN/CLOSE outputs
with T_ON and T_OF duration pulses.
With power equal to 100.0% or 0.0%, the corre-
sponding output remains in modulation.
- T_HI ≠ 0 and T_OF ≠ 0
Floating Valve
This setting is not recommended for use with a valve
without feedback.
The T_HI parameter must always be ignored, and
movement is managed in terms of impulses only.
With power ≤ 10.0%, or ≥ 90.0%, impulse manage-
ment is suspended, and the opening or closing com-
mand is forced until required power falls within the
range of 10.0-90.0%.
In the case of a floating valve, consider that when the
threshold of requested power is exceeded, the valve's
internal model will be updated immediately with the
position 9.9% or 89.9%, as appropriate.
Feedback valve
Parameter T_HI is ignored and all operation is impulse.
112
Warning
With a power of 100.0% or 0.0%, even if the parameters
selected for movement specify impulses, they will not be
implemented.
If a generic movement is required in any valve position, it
will be performed with the specified impulse time, but if
the requested movement leads to 0.0% or 100.0% of the
position, it will be reached while keeping the corresponding
digital output high.
valve
command
TIM.HI
Scroll
Impulsive
intervention
threshold
t0
T_HI ≠ 0 and T_OF = 0
Non impulsive behaviour
valve
command
TIM.ON
Scroll
TIM.OF
T_OF ≠ 0 and T_HI = 0
Impulsive behaviour
With the controller in manual mode, open and close valve
commands can be directly controlled by the OPEN/CLOSE.
In the transition from automatic to manual controller, in the
case of a floating valve, power will be set as equal to the
percentage position reached by the valve just before the
transition. The two values will be similar to the extent that
the drive parameters permit good tracking of power by the
estimated position.
In the transition from automatic to manual controller, in
the case of a floating valve, the presumed position will be
calculated on the basis of the manual power set.
80703B_MHW_2850T/3850T_02-2019_ENG
TIM.LO TIM.LO TIM.LO
t1 t2
TIM.ON TIM.ON TIM.ON
TIM.OF TIM.OF
Time
Time