PPT Slide
PLC faulted or stopped ( Compressor HOA Selectors must be in Hand or Auto ):
- All pumps will modulate on internal vacuum switches
Panel Selector in “Alternate on Time”:
All setpoints in the following description are preprogrammed but can be modified through the supplied Man Machine Interface.
Initialization: ( Use to reset cycle )
.Place control panel Alternation Selector in “OFF”
.Press the “Emergency Stop” button on each compressor.
.Place the selector in “Hand” on each compressor.
.Release the “Emergency Stop” button on each compressor.
.Place the Alternation selector in “Alternate on Time”
.Pump 1 will become the Lead Pump and it’s Auto light will illuminate.
.The other pump’s Auto light will not illuminate until it is called to run by the control panel.
Typical System Operation [Can be modified to suit customer requirements]:
.Lead pump will alternate based on hours of run time.
.Lead pump will run when required and modulates on it’s internal switch.
.Vacuum ( sensed by a redundant transmitter ) falls to Primary Lag Pump start level for a programmed time
.Lead pump is locked out ( modulation locked out ) and Primary Lag Pump is started
.Primary Lag Pump modulates
.Vacuum falls to Secondary Lag Pump start level for a programmed time.
.Primary Lag Pump is locked out and Secondary Lag pump is started
.Secondary Lag Pump modulates
.Vacuum rises to Secondary Lag Pump stop level for a programmed time
.If the Secondary Lag Pump has run for it’s programmed minimum run time it shuts down
.The Primary Lag pump is unlocked and it modulates.
.Vacuum rises to Primary Lag Pump stop level for a programmed time
.If the Primary Lag pump has run for it’s programmed minimum run time it shuts down.
.The Lead Pump is unlocked and it modulates.
Should a pump fault it is taken out of sequence and the next pump takes it’s place. Alarms are annunciated on the control panel and at the pump and are available to the customers alarm systems.