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BOX STACKING CONTROL
A typical application requires the control of a conveyor belt which feeds a
mechanical stacker. The stacker can stack 12, 24, 32, or 48 cartons of ceiling
tile onto each pallet
(depending on pallet size)
. When the required number of
cartons have been stacked, the conveyor is stopped until the loaded pallet is
removed and an empty pallet is placed onto the loading area. Also, it is required
that only the foreman be allowed to change the number of cartons per pallet.
A single preset Libra counter is used to satisfy all the above requirements.
Terminal 3 and terminal 4 of a Model RR Photo-electric sensor
(which feeds a
count pulse to the Libra after each carton passes by)
are respectively connected
to the
“+12 VDC”
and
“CNT. IN”
terminals of the Libra counter. The normally
closed contact of relay 1 is connected to the conveyor belt drive control. A
remote reset button is connected to the
“REM. RST.”
terminal of the Libra
counter, which allows the operator to reset the system from the forklift, after an
empty pallet is placed onto the loading area. Also, a key switch is connected to
the
“PGM. DIS.”
terminal, which allows only the foreman to change the preset
value. The DIP switches are set as follows: DIP switch 1 is set to
“SRC.”
so the
count will increment after the box has passed by the sensor
(count on dark to
light transition)
. DIP switch 2 is set to
“LO. FRQ.”
and DIP switch 3 is set to
“HI BIAS”
, both of which provide extra noise immunity on the input. DIP
switch 4 is set to
“DIS. RST.”
position, which prevents resetting the unit from
the front panel. The unit is set for Mode 0 operation, switches 5 through 8 are
in the
“UP”
position
(Latch Output at Preset, Manual Reset to Zero)
.
The system operation is as follows: as the trailing edge of the box passes the
photo-electric, a count is registered on the Libra display. When the preset value
is reached, the conveyor belt will turn off. The forklift operator removes the
loaded pallet. After the empty pallet is in position, the forklift operator presses
the remote reset switch, which then starts the whole cycle over again.
APPLICATION FOR SINGLE PRESET LIBRA COUNTER
APPLICATION FOR DUAL LEVEL PRESET LIBRA COUNTER
THE CONTROL OF A PAPER ROLL
MANUFACTURING PROCESS
In a paper production process, the requirement exists to control a solenoid which places
a red ink marking at the end of a roll of printing paper
(this marking is used to indicate
when the end of the roll is near)
. The unit must also stop the system when the proper
amount of paper is wound onto the roll. Then, the cutting knife is manually actuated which
shears off the paper. The full roll is taken off the spool and a new roll is loaded on. The
system is then started up again. The Libra two preset counter satisfies these requirements.
The Libra set-up is as follows: Preset 1 is set to 30
(30 ft. {9 M} is desired length of
red marking at the end of the roll)
. When the system is started, the ink marker solenoid
is activated which starts marking the paper
(this is connected to the normally closed
contact of relay 1)
. When 30 is reached, output 1 fires which de-energizes the ink
solenoid. Preset 2 is set to 3400 feet.
(3400 ft. {1036 M} is the total desired length of
paper wound onto the roll)
. When the unit reaches 3400 feet, preset 2 fires which de-
energizes the entire system
(the system control is connected to the normally closed
contact of output 2)
. The operator then activates the knife, which shears off the paper
and at the same time, the Libra counter is reset and is ready for the next cycle.
An LSC
(length sensor)
with a 1 pulse/foot wheel is connected to the Libra counter.
The red
(+12 V)
, black
(COMM.)
and white
(COUNT)
of the LSC are connected to the
Libra
“+12 VDC”
,
“COMM.”
, and
“CNT. IN”
terminals respectively. The
“PGM.
DIS.”
terminal is left unconnected so preset values can be changed
(a key switch can be
used if desired)
.
“RESET”
is connected to the knife actuator so when the knife shears
off the paper, the Libra counter is reset. DIP switch 1 is set to current sinking to match
the LSC output. DIP switch 2 is set to
“LO FRQ.”
because the count speed cannot be
greater than 100 Hz. DIP switch 3 is set to
“HI BIAS”
. The front panel reset enable
switch
(DIP switch 4)
is set to
“DIS.”
. All the mode switches are set
“UP”
, which is
mode 0
(Latch Outputs at Presets and Manual Reset to Zero)
. The relay contacts are
connected as previously discussed.
ORDERING INFORMATION
LIBC2E00
LIBC2E10
Dual Preset LED Libra Counter
LIBC2E
For more information on Pricing, Enclosures & Panel Mount Kits refer to the RLC Catalog or contact your local RLC distributor.
LIBC1E00
LIBC1E10
Single Preset LED Libra Counter
LIBC1E
LIBC2000
LIBC2010
Dual Preset LCD Libra Counter
LIBC2
LIBC1000
LIBC1010
Single Preset LCD Libra Counter
LIBC1
115 VAC
230 VAC
DESCRIPTION
MODEL NO.
PART NUMBERS FOR
AVAILABLE SUPPLY VOLTAGES
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