B-3
OPERATION
PRISM® SUSPEND 4000
SOFTWARE FUNCTIONS
The Prism® Suspend 4000 is controlled by a PLC with the
following software functions:
1)
FAN START/STOP -
Fan start/stop is controlled by push button on front of the
control panel when in manual mode OR by weekly timer
schedule when in auto run mode. When in auto run mode, fan
can still be stopped/started with the push button, but will be
temporary until the next scheduled start/stop time is
reached.
2)
FAN OPERATION -
When the electrically commutated fan is running, the PID
controller in the PLC references internal "duct" pressures to
control fan airflow output. Users can set the desired airflow on
the PLC screen. The default airflow is set at 4000 cfm
which
equates to an internal "duct" pressure of 584 Pa. Fan
output is
limited during a filter cleaning cycle and when a
damper
malfunction is detected. The following chart is the
relationship
between airflow and internal "duct" pressure.
3)
AUTOMATIC FILTER CLEANING -
Filter cleaning is dependent upon the differential pressure
across the filters and the cleaning threshold set point. The
Prism® Suspend 4000 Adaptive Cleaning Technology first
initiates filter cleaning at 500 Pa and the threshold gradually
increases to a maximum of 1500 Pa at which point a filter
change automatically resets the threshold to 500 Pa.
Filter differential pressure is measured after the fan speed
has
stabilized. When initiated, the automatic cleaning cycle
consists of the following steps:
A)
Fan speed slows.
B)
Inlet dampers close.
C) When damper actuator switch confirms dampers are
closed, fan speed rises to preset cleaning threshold.
D)
Pulses of compressed air are generated and controlled
with the following parameters that can be changed by
the
user-
(1)
Pause Time (default
20
sec)
(2)
Pulse Time (default 200 ms)
(3)
Number of cycles (default 2 for total of 4 pulses)
E)
After cleaning pulses complete, fan speed
slows.
F)
Unit runs at steady state to allow dust to settle.
G)
Dampers open.
H) Fan restarts to meet airflow set point.
NOTE: A cleaning cycle can be manually initiated by
pressing the
TEST
button for more than
4
seconds.
AUTO MODE SCHEDULE -
To enable auto run mode, unit must be in standby mode.
Toggle to the password screen by hitting the left arrow key.
Enter the password (1234), then arrow to the first schedule
screen (HW1). Press the ALT button to highlight the
"enable" box. Press the down arrow to add check mark,
then hit the OK button. Unit will automatically start if current
time falls within scheduled on time. Fan can be turned off
manually while in auto mode by pressing the fan start/stop
button.
There are two timers available to control on/off function of
the unit. Each timer has 7 days to set on - off times for. To
set the schedule, follow these steps:
Follow auto mode enable menu steps to access
schedule
menus.
A)
The two timers are labeled HW1 and HW2.
B)
Set the number of timers needed. For example, if
Monday from 6am to 5pm on time is
desired, set the parameters as follows -
(1)
DAY = MON
(2)
ON = 6:00
(3)
OFF = 17:00
C)
For timers that are not needed, set the timers so
ON=00:00 and the OFF=00:00.
B
)
Intake damper malfunction is indicated with a flashing
red light (
two
second
s
on /
0.1
seconds off). Two
damper malfunctions can trigger this light.
When
dampers close for filter cleaning, the actuator switches
must provide a "high" signal to the PLC (AuxIn1 &
AuxIn2) to indicate dampers are fully closed.
If this
signal
is not received
within 1 minute, unit will enter
"LIMP" mode. When
dampers are supposed to be open
(all times except for
filter cleaning), the actuator
switches must provide a
"low" signal to the PLC to
indicate dampers have
opened (moved from the closed
position).
If one damper fails to open, the unit will enter
"Limp" mode which limits fan speed to 50%. If both
dampers fail to open, the fan will not run. When unit is
running in "Limp" mode, the unit will not run the filter
cleaning cycle.
Once dampers
have been repaired,
press
the
TEST
button to
initiate damper
testing. If the test is
passed, unit will
automatically
resume normal operation.
C
)
EC fan motor malfunction is indicated with a solid red
light. The light will turn off when the malfunction has
been resolved.
D
)
Insufficient supply of compressed air is indicated with a
flashing red light (0.1 seconds on / 2 seconds off). This
alarm is triggered if air pressure falls below 5 bar (73
psi) at the air regulator and the unit will not initiate filter
cleaning in this state. For best filter cleaning
performance, set the air regulator at 6 bar (87 psi).
AIRFLOW
(CFM)
Internal Duct
Pressure
(PA)
3000
329
3250
386
3500
447
3750
514
4000
584
4)
ALARMS -
The PLC will trigger an alarm in the following cases:
A)
The filter change alarm set at 1500 Pa is indicated
with a flashing red light (two seconds on / two
second
s
off). Early alert to order filters is indicated
when
ashing light shuts off within 2 minutes of unit
restart
after filter cleaning. When flashing light
remains
constant, filter change is required to
maintain normal
unit operating performance. This
alarm will
automatically reset after filters are
changed and unit
restarted.
5
)
