Ingersoll-Rand EP 20 SE, Варианты руководства оператора/инструкции по эксплуатации, Страница: 28 / 70

Modulate/ACS Control (Continued)
The compressor will then operate to deliver full
capacity air to the plant system. If the plant air
system pressure rises to that of the Intellisys off line
set point, pressurized air will be sent to the inlet
valve causing it to close, and to the blowdown valve,
causing it to open.
The compressor will continue to run unloaded, but
since pressure levels have reduced, it will do so with
a minimum power draw.
The Intellisys
®
has a fixed minimum differential of 10
psi between the off line air pressure setting and the
on line air pressure setting. The differential may be
increased by adjusting the on line air pressure
setting of the Intellisys
®
.
Refer to Section 3.5 for instructions.
The automatic control selector (ACS) is designed to
continuously monitor the plant air demand and
select either the on line-off line, or the modulate
control mode - whichever is most desirable at
anytime during an operating day.
It allows the compressor to operate in its most
efficient mode without attendance, thereby reducing
power costs to a minimum.
When the compressor operates in the on line-off line
control mode, the length of time the compressor
remains in the "off line" condition is an indication of
the plant air demand. Intellisys controller is sensing
and awaiting a sufficient line pressure decrease
before signaling a shift to the on line mode. If the
"off line" time period is relatively short, thereby
indicating a high demand for air, it is preferable to
shift the control system to upper range modulation.
The Intellisys
®
does this, and does it automatically if
the compressor unloads 3 times within a 3 minute
time period.
If later, the plant demand decreases, and even
under modulate control the line pressure reaches
the setting of the Intellisys
®
controller, and the
control shifts to the "off line" mode, the time in this
mode will still be monitored. A long "off line" time-
period indicates a low plant air demand, indicating
the desirability of operating in the on line-off line
mode.
The Intellisys
®
then does this, and does it
automatically if the compressor operates unloaded
for more than 3 minutes.
Modulation Only
If MODULATION ONLY is turned on in the set point
routine, the unit will shift to Modulation control mode
immediately when the unit is running. The 3 cycles
within 3 minutes time period required for ACS to
change to Modulation mode is bypassed. The unit
will stay in Modulation mode until the unit runs
unloaded for 3 minutes (the unit then returns to ACS
control) or MODULATION ONLY is turned off via the
set routine.
Delay Load Time
This is the amount of time the line pressure must
remain below the online set point before the
compressor will load or start (if the unit was stopped
due to an auto start/stop situation). Setting the load
delay time to 0 will cause no delay. When the delay
load timer becomes active, the display will switch to
package discharge pressure (if not displaying
package discharge pressure at that time) and then
display the delay load count down. Once the count
down reaches 0, the unit will load or start and the
display will return to line pressure. The display select
button is inactive during the delay load count down.
MODEL RATED
OPERATING PRESSURE
EP 125 PSIG
HP 140 PSIG
HXP 200 PSIG
26