18 ATR171 - User manual
• In case of power failure or after a switch-off , at restart both the manual
functioning and the previously fi xed output percentage value will be maintained.
• If during automatic functioning there is a sensor failure, controller will
automatically switch to manual mode while maintaining command output
percentage unchanged as generated by P.I.D. immediately before failure.
8.6 Soft-Start
At switch-on the controller follows a rising gradient expressed in units (ex. degree/
hour) to reach the setpoint.
The chosen rising gradient in Unit / Hour must be set on parameter 73
ri . G r .
; at next
switch-on the controller will execute Soft Start function.
Automatic and manual Tuning function cannot be enabled if Soft Start function is
active. In model ATR171-23ABC-T the Soft-Start function may be enabled only if
dip-switches are confi gured for serial communication (AI2 desabled).
8.7 Pre-programmed cycle
This function allows to program a simple working cycle on time basis, and can be
enabled setting
p r. cy .
on parameter 70
op.mo.
: process reaches setpoint1 according
to gradient set on parameter 73
Grad.
, then it reaches setpoint2 with the maximum
power.
Once reached setpoint2, process is hold for the time set on parameter 75
m a . ti .
.
At expiry, process reaches environmental temperature according to gradient set on
parameter 74
f a . G r.
and then command output is disabled and controller visualizes
stop
.
It is possible to handle Start/Stop also by digital input
It is also possible to modify parameters of pre-programmed cycle from user menu
setting parameter 76
u.m.c.p.
To start modifi cation, press FNC.
Setpoint
Setpoint 2
Max.
power
Setpoint 1
Hold
Natural cooling
Time
Gradient
Cycle starts at each switch-on of the
controller.
In model ATR171-23ABC-T the pre-programmed cycle function may be enabled only
if dip-switches are confi gured for serial communication (AI2 desabled).
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