Sullair SD-600 - 3.2.3 Operating Sequence (DDS Option)

INSTALLATION, START-UP & MAINTENANCE MANUAL
MODEL NO.: SD-220 TO SD-600- DDS OPTION
REV 0 – May 24,,.2001
15
SECTION 3
3.2.3 Operating sequence (DDS Option)
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SD-220-DDS – SD-600-DDS heatless air dryer uses a PLC as its
standard controller. In the event of a power failure, the inlet valves remain in their
position, and the exhaust valves will close and dryer will pressurize both chambers.
The dryer will return to the same step in the cycle dryer was in before power was
lost. (See NOTE 2)
Energizing control panel: Power is turned ON – electrical circuit energized.
STEP 1 SELECT LEFT CHAMBER DRYING.
- De-energize solenoid EV-1R.
- Energize solenoid EV-1L.
- Inlet valve positioned for left chamber drying.
- When 3 seconds have passed, go to STEP 2
STEP 2 RIGHT CHAMBER DE-PRESSURIZATION.
- Keep energized EV-1L
If not in DDS mode:
- Energize EV-2R opening right chamber dump/exhaust valve.
If in DDS mode and dewpoint is better than hygrometer setpoint:
- EV-2R does not energize.
When regeneration time has passed, go to STEP 3
STEP 3 RIGHT CHAMBER REPRESSURIZATION.
- Keep energized EV-1L.
- De–energize EV-2R closing right chamber dump/exhaust valve.
- The repress timer begins a countdown of 45 sec. (See Note 1)
- Inlet valve remains in current position.
- When repressurization time has passed, go to STEP 4
STEP 4 RIGHT CHAMBER DRYING.
- De-energize solenoid EV-1L
- Energize solenoid EV-1R.
- Inlet valve positioned for right chamber drying.
- When 3 seconds have passed, go to STEP 5
STEP 5 LEFT CHAMBER DEPRESSURIZATION.
- Keep energized EV-1R
If not in DDS mode:
- Energize EV-2L opening right chamber dump/exhaust valve.
If in DDS mode and dewpoint is better than hygrometer setpoint:
- EV-2R does not energize.
When regeneration time has passed, go to STEP 6