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6. Controller – Level 1
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6. Controller – Level 1
Time (refer to Table 6-3)
t0
t1
t2
t3
t4
t5
t6
t7
t8
Process valve name
(Process valve state
w/ de-energized
pilot solenoid valve)
Left Tower Drying
Right Tower Regenerating
Half Cycle
Right Tower Drying
Left Tower Regenerating
Half Cycle
Left purge valve
(normally closed)
Pilot Energized
(open)
Left inlet valve
(normally open)
Pilot Energized (closed)
Right inlet valve
(normally open)
Pilot Energized (closed)
Right purge valve
(normally closed)
Pilot Energized
(open)
Normal status of pressure switches
Left tower
pressure switch
closed
closed
closed
closed
closed
closed
closed for < 5
sec. then open
open at t7,
closed before t8
Right tower
pressure switch
closed
closed
closed for < 5
sec. then open
open at t3,
closed before t4
closed
closed
closed
closed
Pressure switch status that causes an alarm
Left tower drying
Low tower pressure
a
open
1
open
1
Left tower regenerating
Fail to de-pressurize
b
closed
1
Left tower regenerating
Fail to re-pressurize
c
open
2
Right tower drying
Low tower pressure
d
open
1
open
1
Right tower regenerating
Fail to de-pressurize
e
closed
1
Right tower regenerating
Fail to re-pressurizef
open
2
Note
Stop cycle on
fault?
Comments
1: Check for fault condition at 15,
25, 35,... seconds into the half-cycle
no
If the fault condition is clear for 2 cycles: the alarm LED stays on (without blinking); the tower and pressure switch LEDs
stop blinking (return to normal operation). Once the fault condition is clear, pressing the reset button will clear the alarm
LED (and the tower and pressure switch LEDs if they're still blinking).
2: Check for fault condition just
before the end of the half-cycle
yes
If the fault condition clears: resume cycling; the alarm LED stays on (without blinking); the pressure switch LED stops
blinking (returns to normal operation). Once the fault condition is clear, pressing the reset button will clear the alarm
LED.
a: Blink the following LEDs: Alarm + P1 + Left tower drying
b: Blink the following LEDs: Alarm + P1 + Left tower regenerating
c: Blink the following LEDs: Alarm + P1
d: Blink the following LEDs: Alarm + P2 + Right tower drying
e: Blink the following LEDs: Alarm + P2 + Right tower regenerating
f: Blink the following LEDs: Alarm + P2
Table 6-4
Event Sequence and Component Status – Level 1 Controller