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is the secondary pressure band which defines alternative pressure set points that can be activated by a
timer or control input. Both pressure band settings use the same type of interface and data entry, described
below.
The
p1 Pressure Band
defines the default pressure set points of the compressor. The
p1
Pressure Band
Settings
screen will look like Figure 76 below.
Figure 76: p1 Pressure Band
There are five parameters on the pressure band setting screen:
Load, Target, Unload, Warn,
and
Fault.
Load pressure
This value is the pressure at which the compressor will open the inlet valve and begin producing air after
an unload, blowdown, or stop sequence occurs. If the motor is not already running and the compressor has
been enabled, the motor will be started when the pressure drops below the load pressure. This value must
be set lower than the
Target Pressure
value.
Target pressure
This value is the pressure set point of the compressor. This is the pressure that the compressor attempts
to maintain throughout daily operation. This is typically a value between the
load
and
unload pressure
. On
variable speed machines the motor speed will be controlled to match this pressure set point. On machines
with inlet and turn-valve modulation the machine will modulate to match this set point.
Unload pressure
This value is the pressure at which the compressor will close the inlet valve and begin the unload or
blowdown sequence.
Warn pressure
This value is the pressure where the controller will flag a machine warning, meaning the pressure is
reaching a critical level that is higher than the machine
unload pressure
value.
Fault pressure
This value is the pressure where the controller will flag a fault and shutdown the machine. This is a condition
that will need to be taken care of immediately and reset at the controller HMI.
Any of the values can be set or changed by selecting the input box. A number keypad will come up for data
entry. For example
, Target pressure
value entry screen will like if Figure 77 below.
