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4.9 - SOFT-START FUNCTION
All the parameters referred to the Soft -Start functioning are contained into the group
“
]
rEG”.
The Soft-Start function is only working with PID control and allows the limiting of the control power when the instrument is
switched on, for a programmable time.
This is useful when the actuator, driven by the instrument, could be damaged by power too high supplied when the
application is not yet in the normal rating. (ex. for certain heating elements).
The functioning is depending on the following parameters :
“St.P”
– Soft-Start power
“Sst”
– Soft-Start time (expressed in hh.mm)
The possible functioning modes are the following :
1)
If both parameters are programmed with values different from OFF, at the switch on, the instrument gives an output power
as programmed on par. “St.P” for the time programmed on par. “SSt”. In the practice, the instrument works in manual
condition and commutates into automatic control at the elapsing of time “SSt”.
It’s advisable not to program a power “St.P” too high because the function is not deactivated when the automatic control
power results lower than the programmed one.
2)
If par. “St.P” = OFF and on par. “SSt” is programmed a value, at the switch on, the power calculated by the PID controller is
divided for the time “SSt”, with the meaning to calculate a ramp. The output power starts from 0 and is progressively
increased, basing on the calculated ramp, up to the reaching of time “SSt” or until when the power overcomes the power
calculated by the PID controller.
To disable the Soft-Start function it’s enough to program par. “Sst” = OFF
Whenever, during the Soft-Start execution, should occur a measuring error, the function is interrupted and the instrument
gives an output power as programmed on par. “OPE”.
If the measuring is restored, the Soft-Start is in any case deactivated.
Note :
When the Soft-Start is active, it’s not possible to execute the Autotuning, because it may gives an excessive power.
Consequently, if one of the Soft-Start parameter is different from OFF and the Autotuning is activated, on the display will
appear the error message
“ErAt”.
If
it’s desired to execute the Autotuning together with the Soft-Start function activated, it’s necessary to start manually the
tuning (“Auto”=3) when the actuator is in the normal rating which will not cause any damage.
4.9 – ALARMS FUNCTIONING (AL1, AL2, AL3)
4.9.1 – ALARM OUTPUTS CONFIGURATION
The alarms are depending on the process value (AL1, AL2, AL3) and before to set their functioning it’s necessary to establish
to which output the alarm has to correspond to.
First of all it’s necessary to configure, in the parameters group
“
]
Out”,
the parameters relative to the outputs required as
alarm (“O1F” , “O2F” ,“O3F” ,“O4F”) programming the parameter relative to the desired output as follows :
= Alno
if the alarm output has to be ON when the alarm is active, while it’s OFF when the alarm is not active
= Alnc
if the alarm output has to be ON when the alarm is not active, while it’s OFF when the alarm is active
Note:
In the following examples the alarm’s number is generally indicated as
n
Have now access at the group
“
]
ALn”,
relative to the alarm which is desired to be set, and program on par.
“OALn”
, to which
output the alarm signal has to be sent.
The alarm functioning is instead defined by parameters :
"ALnt "
– ALARM TYPE
"Abn"
– ALARM CONFIGURATION
“ALn”
– ALARM THRESHOLD
“ALnL”
– LOW ALARM THRESHOLD (for band alarm)
“ALnH”
- HIGH ALARM THRESHOLD (for band alarm)
“ALnd”
– ALARM ACTIVATION DELAY (in sec.)
"ALni"
– ALARM BEHAVIOUR IN CASE OF MEASURING ERROR
