18
Model BB4000 Controller Instruction Manual
8. d
Iscrete
I
nput
f
unctIons
The following is a description of the Functions that may be assigned to the Discrete Inputs using
Parameters F.01 - F.18:
Notes:
1. All Discrete Inputs are originally programmed with default Functions, but they may be
changed at any time using Parameters F.01 - F.18.
2. Each of the Functions may only be assigned to one Discrete Input. If assigned to more
than one Input, the Fault indicator will come on and Fault Code 8 will be generated.
8.1. Pump 1 (2, 3, 4) Disable - Functions 1-4
With Parameter P.52 = 0 (Normal Mode)
When a Discrete Input programmed as a “Pump 1 (2, 3, 4) Disable” is
closed, the
respective pump will be disabled (not allowed to run) and skipped over in the pump
call sequence.
With Parameter P.52 = 1 (Logic Inverted Mode)
When a Discrete Input programmed as a “Pump 1 (2, 3, 4) Disable” is
open, the
respective pump will be disabled (not allowed to run) and skipped over in the pump
call sequence.
Whenever a pump is disabled, the next available pump is called in its place when needed. The
one exception to this is the Alternation Sequence - Pump 1 Always Lead (Parameter P.16 = 3),
where disabling pump 1 will not result in another pump taking its place.
8.2. Level Freeze - Function 5
When a Discrete Input programmed for “Level Freeze” is first closed, the Wet Well Level is held
steady or frozen so that a bubbler system’s bubbler tube may be purged without causing the
Level to jump up or down. The external logic that performs the bubbler tube purge must pro-
vide the Discrete Input closure prior to a significant change in the 4-20 mA analog Level input.
The Level Freeze logic keeps the Level frozen for 10 seconds and then releases it, regardless of
whether the discrete Input had re-opened or not. It does not matter how long the input remains
closed, but it must be opened to reset the logic.
8.3. External Alternation - Function 6
Each time the Discrete Input programmed fro “External Alternation” transitions from open
to closed, alternation of the pumps will occur. It does not matter how long the input remains
closed, but it must be opened to reset the logic. If no pumps were running when the Discrete
Input is closed, the alternation of the designated lead pump will still occur. Typically this input is
connected to contracts from an external Time clock.