ascon G2 Series - Page 37

36
7 - Programmed Setpoint
7.2.1 MAXIMUM ALLOWED
DEVIATION (
bbaanndd
)
If the PV controlled input value exceeds
the band, centred around the SP, the
segment time is extended of the same
time the PV input stays out of the band.
The band width is defined in a para-
meter of the program segment.
The actual segment period is calcu-
lated as ti..== +Ti
B. Dwell
àti.--
ti.-- + Ti
Ti
PV
SP
àband
àband
A. Ramp
àti.--
àti.-- + Ti
Ti
àband
PV
SP
àband
The parameter #fail . specifies
the behaviour of the programmer at
power up (see pag.37). Selected
between the following 3 choices:
#Cont Continue
#res Reset
#raMp Ramp
If
#Cont is selected,
the execution of the program starts
from the point reached at the power
failure time.
All the parameters, like Setpoint
and the remaining time are restored
at the values they had at power off.
If
#res is selected,
at power on the program ends and
goes back to local mode.
If
#raMp is selected,
the execution of the program starts
from the point reached at the power
failure time.
In this case, the programs contin-
ue with PV reaching SV with a
ramp, whose slope corresponds to
the one of the segment running at
the power off.
PV
ti
SP
Power Off
Power Off time
The drawing below illustrates the
situation.
Power off during a dwell
Power off during a ramp
ti
Power Off
Power Off
7.2 SETPOINT PROGRAMMER OPERATION
7.2.2 RE-START OF A PROGRAM AFTER A POWER FAILURE
M5 UK•ed4 10-12-2004 16:20 Pagina 36