Filter
Top Products
2–Pump 12-Station Controllers Chapter 4: Operation 41
Label Description
LOADING
Following the IDLE (Startup) state, the vent valve is closed and the first
station in demand loads when that station sequence valve opens. This is the
LOADING state. You can define load times for each station. The controller
loads the station in demand until one of the two events below occur:
1. The volume fill sensor becomes active.
2. The load time is exhausted.
At the end of the LOADING cycle, the controller closes the sequence valve
and continues to the next station in the queue. If all stations are satisfied, the
controller enters the IDLE (No Activity) state.
IDLE
(No Activity)
The IDLE (No Activity) state acts as an energy saver and pump lifetime
extender. During this state, the atmospheric valve is open, allowing the
vacuum to be vented. All sequence valves are closed and all inputs are
monitored for demand activity. This feature reduces repeated starting and
stopping of pumps, extending pump operation life.
If the controller senses a demand during the IDLE (No Activity) state, the
controller re-enters the LOADING state by closing the vent valve and opening
the sequence valve of the station in demand.
If no demand exists in the system for the duration of the IDLE (No Activity)
time setting, the controller then enters the READY state.
Note: IDLE is any condition in the conveying system when the pump
runs but no station loads.
READY
The READY state is a monitoring function. All outputs are off and the
controller waits for a demand signal to be fulfilled. If the controller senses a
demand condition, the controller then re-enters the STARTING state and
returns to load material into the hoppers.
BLOWBACK
When enabled, the controller enters the BLOWBACK state following a user-
definable number of station loads. The blowback function is to pulse air
through the filter system to keep the filter from clogging. The number and
duration of the air pulses is also user-definable; see the Blowback menu on
Pages 54-58 for more information.
LOADING/IDLE
(2 Pump Mode
Only)
In Dual Pump mode, if you start the controller with demand from stations
assigned to both pumps, both pumps start at the same time. In many plants,
such a resulting power surge can momentarily exceed the electrical limits of
the plant. To prevent this condition, the pumps are staged in sequence
separated by a short duration. Pump 1 always starts first, followed by Pump 2.
This state also applies when both pumps are in the OFFLINE state and
demand occurs on both systems at the same time.