Bulletin No. LIBC-J
Drawing No. LP0103
Released 10/04
Tel +1 (717) 767-6511
Fax +1 (717) 764-0839
www.redlion.net
MODEL LIBC - LIBRA SERIES COUNTERS (LCD & LED)
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ABILITY TO LOCK OUT FRONT PANEL FUNCTIONS
SEALED FRONT PANEL CONSTRUCTION (NEMA 4/IP65)
ONE OR TWO PRESET VERSIONS
0.5" HIGH LIQUID CRYSTAL DISPLAY OR 0.4" HIGH LED DISPLAY
ACCEPTS INPUT COUNT RATE UP TO 2500 CPS
BI-DIRECTIONAL COUNTING
SOLID-STATE CURRENT SINK OUTPUT(S)
FORM C RELAY OUTPUT(S)
PROGRAMMABLE TIMED OUTPUT (0.01 sec to 99.99 sec.)
SIMPLE FRONT PANEL FOR PROGRAMMING EASE
FRONT PANEL PROGRAMMABLE DECIMAL POINTS
MEETS DIN PANEL MOUNT SPECIFICATIONS
REMOTE RESET CAPABILITY
NON-VOLATILE MEMORY (E
2
PROM)
ON-LINE SELF-TEST
DESCRIPTION
The Libra Series of presettable counters is an economical and reliable solution
to one or two preset level requirements. The LIBC1 and LIBC1E are the single
preset versions and the LIBC2 and LIBC2E are the dual preset versions. All four
units have a solid-state output and a Form C relay output for each preset. These
units feature input configuration programmability, a full complement of control
inputs, programmable timed outputs, non-volatile memory, and many other
features which will satisfy most any single or dual preset level requirement.
The Libra counters have two main counting actions, Reset to Zero
(RTZ)
and
Reset to Preset
(RTP).
With RTZ, the counter resets to zero and counts up
(if
UP/DN terminal is at high level)
and activates the outputs when the preset
value(s) are reached. When RTP is used, the unit starts at the preset value and
counts down
(if the UP/DN terminal is at low level)
and activates the output
when zero is reached. For the 2-preset version, the count starts at preset 2 and
counts toward zero. Output 1 fires when preset 1 value is reached and output 2
fires when the count reaches zero. There are eight modes of operation for the
single preset unit and sixteen modes of operation for the dual preset unit.
The timed output is programmed through the front panel buttons and can be
programmed from 0.01 sec. to 99.99 sec.
(The unit’s timed output is set at the
factory to be 0.1 sec.)
The Libra counters have an internal non-volatile memory
device which eliminates the need for battery back-up. When input power is
removed, this device will maintain all data necessary for system operation. A
Program Disable terminal is available, which is used to prevent accidental
changes or tampering by unauthorized personnel to the preset(s) or timed output
value(s). The front panel reset button can also be enabled or disabled by a rear
panel DIP switch. These counters also have an on-line self-test, which checks
all display driver and micro-processor hardware. The self-test can be run at any
time without losing counts or missing a preset value.
Power, input, and output connections are made via removable terminal strips
located at the rear of the unit. These strips can accept one #14 AWG stripped
wire. DIP switches at the rear of the unit are used to program the input
configuration and to set the desired operating modes.
The Libra Series counters have a metal die-cast front bezel, which is sealed,
and meets NEMA 4/IP65 specifications for wash-down and/or dust when
properly installed. Mounting clips are provided for easy panel installation.
SAFETY SUMMARY
All safety related regulations, local codes and instructions that appear in the
manual or on equipment must be observed to ensure personal safety and to
prevent damage to either the instrument or equipment connected to it. If
equipment is used in a manner not specified by the manufacturer, the protection
provided by the equipment may be impaired.
Do not use this unit to directly command motors, valves, or other actuators
not equipped with safeguards. To do so, can be potentially harmful to persons
or equipment in the event of a fault to the unit.
CAUTION:
Read complete instructions
prior to installation
and operation of the unit.
CAUTION:
Risk of electric shock.
DIMENSIONS In inches (mm)
Note: Recommended minimum clearance (behind the panel) for
mounting clip installation is 2.7" (69 mm) H X 4.5" (114 mm) W.
1
SPECIFICATIONS
1.
DISPLAY:
4-digit, 0.5"
(12.7 mm)
high LCD display.
4-digit, 0.4"
(10.2 mm)
high LED display.
2.
POWER REQUIREMENTS:
AC Operation:
115/230 VAC (±10%), 50/60 Hz, 6 VA
(LCD)
or 9 VA
(LED).
DC Operation:
11 to 14 VDC @ 0.2 A max.
(LCD)
or 0.3 A max.
(LED).
3.
SENSOR POWER:
+10 to 16 VDC @ 150 mA.
4.
COUNT INPUT:
Switch selectable to accept count pulses from a variety of
sources including switch contacts, outputs from CMOS or TTL circuits, and
all standard RLC sensors.
Current Sourcing
- Unit provides 3.9 KΩ pull-down load for sensors with
current sourcing outputs.
(Max. input voltage 28 VDC @ 7 mA)
Current Sinking
- Unit provides 7.8 KΩ pull-up load for sensors with
current sinking outputs.
(Max. sensor current, 1.6 mA)
Debounce
- Damping capacitor provided for switch contact debounce.
Limits count speed to 100 Hz max. and input pulse widths of 5 msec min.
Lo Bias
- Input Trigger levels V
IL
= 1.5 V, V
IH
= 3.75 V.
Hi Bias
- Input Trigger levels V
IL
= 5.5 V, V
IH
= 7.5 V.
Note: Bias levels ±10% @ 12 VDC sensor voltage. These levels vary
proportionally with the sensor supply voltage.
5.
MAXIMUM COUNT RATES:
High Frequency
- 2.5 KHz max. for all electronic sensors under all modes of
operation. Signals can be square wave inputs or inputs with negative going
pulse widths, as short as 50 µsec, with a total min. period of 400 µsec.
Low Frequency
- 100 Hz for switch contact closures.
(Note: These units will
operate with VCM [E-H] modules.)
6.
CONTROL INPUTS:
Remote Reset
- Active low (V
IL
= 0.5 V max.), internally pulled up to 5
VDC through a 10 KΩ resistor (I
SNK
= 0.5 mA). Response time = 10
msec. A low will reset the unit and deactivate outputs.
Program Disable
- Active low (V
IL
= 0.5 V max.), internally pulled up to 5
VDC through a 10 KΩ resistor (I
SNK
= 0.5 mA). A low will inhibit the
changing of presets, decimal point selection, and timed outputs, as well as
testing outputs in self-test.
Up/Dn Control
- Active low (V
IL
= 0.5 V max.), internally pulled up to 5
VDC through a 10 KΩ resistor (I
SNK
= 0.5 mA) Response Time = 150
µsec. This input determines the direction of the count and is independent
of Reset to Zero or Reset to Preset modes of operation. When input is low,
count is down.
7.
OUTPUTS:
Solid-State
- Current sinking NPN open collector transistors. I
SNK
= 100 mA
max. V
OH
= 30 VDC max.
(Internal Zener diode protection).
One solid-
state output for each preset level. V
OL
= 1 VDC max. @ 100 mA.
Relay(s)
- Form C contacts max. rating 5 amps @ 120/240 VAC, 28 VDC
(resistive load),
1/8 H.P. @ 120 VAC
(inductive load).
The operate time is
5 msec nominal and the release time is 3 msec nominal.
Relay Life Expectancy
- 100,000 cycles at max. rating.
(As load level
decreases, life expectancy increases.)
2
Programmable Timed Output
- The timed output can be programmed from
0.01 sec to 99.99 sec, ±0.01% - 10 msec. The timed output is set for 0.1
sec at the factory.
8.
MEMORY RETENTION:
The Libra counters have a
“no power E
2
PROM”
which maintains all information when the input power is removed. The life
expectancy of this device is at least 100,000 power down cycles and length of
memory retention for a single power down can be as long as 10 years.
9.
INPUT, POWER, AND OUTPUT CONNECTIONS:
There are two plug-
in, compression type, barrier strips located at the rear of the unit. These strips
can be removed from the rear of the unit for ease of wiring. After wiring is
complete, the connector can be plugged back into the unit.
10.
CERTIFICATIONS AND COMPLIANCES:
SAFETY
Type 4 Indoor Enclosure rating (Face only), UL50
IEC 1010-1, EN 61010-1: Safety requirements for electrical equipment
for measurement, control, and laboratory use, Part 1.
IP65 Enclosure rating (Face only), IEC 529
ELECTROMAGNETIC COMPATIBILITY
Immunity to EN 50082-2
Electrostatic discharge
EN 61000-4-2 Level 2; 4 Kv contact
1
Level 3; 8 Kv air
Electromagnetic RF fields
EN 61000-4-3 Level 3; 10 V/m
80 MHz - 1 GHz
Fast transients (burst)
EN 61000-4-4 Level 4; 2 Kv I/O
2
Level 3; 2 Kv power
RF conducted interference
EN 61000-4-6 Level 3; 10 V/rms
2
150 KHz - 80 MHz
Power frequency magnetic fields EN 61000-4-8 Level 4; 30 A/m
Emissions to EN 50081-2
RF interference
EN 55011
Enclosure class B
Power mains class B
Notes:
1. Metal bezel of unit connected with ground lead from rear bezel screw to
metal mounting panel.
2. When the unit is DC powered from terminal TBA pin 5 (common) and
terminal TBB pin 6 (+12 VDC) a power line filter was installed, RLC
#LFIL0000 or equivalent, so as not to impair the function of the unit.
Refer to the EMC Installation Guidelines for additional information.
11.
ENVIRONMENTAL CONDITIONS:
Operating Temperature:
0 to 50°C
Storage Temperature:
-40 to 70°C
Operating and Storage Humidity:
85% max. (non-condensing) from 0°C
to 50°C.
Altitude:
Up to 2000 meters
12.
CONSTRUCTION:
Metal die-cast bezel with black, high impact plastic
insert. Front panel meets NEMA 4/IP65 requirements for indoor use when
properly installed. (Panel gasket and mounting clips included with unit.)
Installation Category II, Pollution Degree 2.
13.
WEIGHT:
1.5 lbs.
(0.68 k)
[LCD], 1.75 lbs.
(0.79 k)
[LED]
MODES OF OPERATION
Mode settings of the switches are shown to the right of the text below. The
mode number corresponds to a binary code, represented by the DIP switch
positions. When the switch is
“UP”,
it is equivalent to a zero. When the switch
is
“DOWN”,
it is equivalent to a one. The mode switch settings can be easily
observed from the panel front by using the self-test. At the end of self-test, the
state of these mode switches are displayed.
NOTES:
1. For all the following modes of operation, when the unit is set for a Reset to
Zero mode, the UP/DN terminal (count direction) is normally left high (in
“UP” position). When the unit is set for a Reset to Preset mode, the UP/DN
terminal is normally tied to common (in “DOWN” position). However, even
though these are the usual conditions for the UP/DN terminal, it does not have
to operate in this fashion. For example: the unit can count down in a Reset to
Zero mode or count up in a Reset to Preset mode and still maintain normal
operating functions.
2. The timed output must be less than the time required to count from the reset
condition to the preset point. Otherwise, the output will appear to be latched-on.
MODES OF OPERATION FOR SINGLE PRESET LIBRA COUNTER
MODE 0 LATCH OUTPUT AT PRESET, MANUAL RESET TO ZERO
In this mode, as the unit counts from zero, the output will latch
on when the preset is reached. When a manual reset
✦
occurs, the
unit will Reset to Zero and the output, if latched on, will unlatch.
Counts will continue to accumulate after the output has turned on.
MODE 1 TIMED OUTPUT AT PRESET, MANUAL RESET TO ZERO
In this mode, as the unit counts from zero, the output will turn
on when the preset is reached. The output will turn off after its
programmed time value has occurred. When a manual reset
occurs, the unit will Reset to Zero. Manual reset
✦
will terminate the timed
output, if the output is still activated. Counts will continue to accumulate after
the preset level has been reached.
MODE 2 & 3 -
✦✦
MODE 4 TIMED OUTPUT AT PRESET, AUTOMATIC RESET TO ZERO AT PRESET
✝
In this mode, as the unit counts from preset, the output will turn on when
zero is reached. The output will turn off after its programmed time value has
occurred. When a manual reset
✦
occurs, the unit will Reset to
Preset and the output, if latched on, will unlatch. Counts will
continue to register after the outputs turn on.
MODE 9 TIMED OUTPUT AT ZERO, MANUAL RESET TO PRESET
✝
In this mode, as the unit counts from preset, the output will turn on when
zero is reached. The output will turn off after its programmed time value has
occurred. When a manual reset
✦
occurs, the unit will Reset to
Preset. Manual reset will terminate the timed output if the output
is still activated. Counts will continue to accumulate after the
output has activated.
MODE 8 LATCH OUTPUT AT ZERO, MANUAL RESET TO PRESET
MODE 10 & 11 -
✦✦
In this mode, as the unit counts from zero, the output will turn
on when the preset is reached. At the same time, the unit will
automatically Reset to Zero and start the cycle over again. The
output will turn off after its programmed time value has occurred. Manual
reset
✦
will turn off the output, if turned on, and reset the count to zero.
During automatic reset, no counts will be lost if the count rate does not
exceed 2,500 cps.
MODE 5 -
✦✦
MODE 6 TIMED OUTPUT AT PRESET, AUTOMATIC RESET TO ZERO AFTER THE
TIMED OUTPUT
✝
In this mode, as the unit counts from preset, the output will turn on when
zero is reached. At this time, the unit will automatically Reset to Preset. The
output will turn off after its programmed time value has occurred.
Manual reset
✦
will turn off the output, if turned on, and reset the
count to preset. During automatic reset, no counts will be lost if
the count rate does not exceed 2,500 cps.
MODE 12 TIMED OUTPUT AT ZERO, AUTOMATIC RESET TO PRESET AT ZERO
MODE 13 -
✦✦
MODE 14 TIMED OUTPUT AT ZERO, AUTOMATIC RESET TO PRESET AFTER THE
TIMED OUTPUT
✝
In this mode, as the unit counts from zero, the output will turn
on when preset 1 is reached. The output will turn off after its
programmed time value has occurred. At the end of the timed
output, the unit will automatically Reset to Zero and start the cycle over again.
During automatic reset, no counts will be lost, as long as the count rate does
not exceed 2,500 cps. Manual reset
✦
will turn off the output, if turned on, and
reset the count to zero.
MODE 7 -
✦✦
✦
In this mode, as the unit counts from preset, the output will turn on when
zero is reached. The output will turn off after its programmed time value has
occurred. At the end of the timed output, the unit will
automatically Reset to Preset and start the cycle over. During
automatic reset, no counts will be lost, as long as the count rate
does not exceed 2,500 cps. Manual reset
✦
will turn off the output, if turned
on, and reset the count to preset.
MODE 15 -
✦✦
Manual reset, either by front panel reset (if enabled) or remote reset, is
always active, and will override any condition or state the counter is
presently in.
✝
When down count is desired, (such as reset to preset modes of operation)
the “UP/DN” terminal must be tied to the “COMM.” terminal.
✦✦
These modes are not applicable to the single preset Libra counter (they
are used only for the two preset counter unit).
MODES OF OPERATION FOR DUAL PRESET LIBRA COUNTER
MODE 0 LATCH OUTPUT AT PRESET, MANUAL RESET TO ZERO
In this mode, as the unit counts from zero, output 1 will latch on when
preset 1 is reached, and output 2 will latch on when preset 2 is
reached. When a manual reset
✦
occurs, the unit will Reset to Zero
and the outputs, if latched on, will unlatch. Counts will continue to
accumulate after the outputs have turned on.
MODE 1 TIMED OUTPUTS AT PRESETS, MANUAL RESET TO ZERO
MODE 2 OUTPUT 1 TURN OFF AT PRESET 2, LATCH OUTPUT 2 AT PRESET 2,
MANUAL RESET TO ZERO
In this mode, as the unit counts from zero, output 1 will turn on when preset
1 is reached, and output 2 will turn on when preset 2 is reached.
The outputs will turn off after their respective programmed time
values have occurred. When a manual reset occurs, the unit will
Reset to Zero. Manual reset
✦
will terminate the timed outputs, if the outputs
are still turned on. Counts will continue to accumulate after the preset levels
have been reached.
✦
In this mode, as the unit counts from zero, output 1 will turn on when preset
1 is reached. When preset 2 is reached, output 2 will turn on and
output 1 will turn off. Output 2 will remain latched on until a
manual reset occurs. Manual reset
✦
will turn off both outputs and
the unit will Reset to Zero. Counts will continue to accumulate after the preset
levels have been reached.
MODE 3 OUTPUT 1 TURN OFF AT PRESET 2, TIMED OUTPUT 2 AT PRESET 2,
MANUAL RESET TO ZERO
Manual reset, either by front panel reset (if enabled) or remote reset, is
always active, and will override any condition or state the counter is
presently in.
In this mode, as the unit counts from zero, output 1 will turn on when preset
1 is reached. When preset 2 is reached, output 2 will turn on and
output 1 will turn off. Output 2 will turn off after its programmed
time value has occurred. When a manual reset occurs, the unit
will Reset to Zero. Manual reset
✦
will also turn off both outputs if they are
still activated. Counts will continue to accumulate after preset levels have
been reached.
(Modes Cont’d)
3
MODES OF OPERATION FOR DUAL PRESET LIBRA COUNTER (Cont’d)
MODE 4 OUTPUT 1 TURN OFF AT PRESET 2, TIMED OUTPUT 2 AT PRESET 2,
AUTOMATIC RESET TO ZERO AT PRESET 2
MODE 10 OUTPUT 1 TURN OFF AT ZERO, LATCH OUTPUT 2 AT ZERO, MANUAL
RESET TO PRESET 2
✝
In this mode, as the unit counts from zero, output 1 will turn on
when preset 1 is reached. When preset 2 is reached, output 2 will
turn on, output 1 will turn off, and the unit will automatically Reset
to Zero. Output 2 will turn off after its programmed time value has occurred.
Manual reset
✦
will turn off both outputs, if activated, and reset the count to
zero. During automatic reset, no counts will be lost as long as the count rate
does not exceed 2,500 cps.
MODE 5 TIMED OUTPUTS AT PRESETS, AUTOMATIC RESET TO ZERO AT PRESET 2
In this mode, as the unit counts from preset 2, output 1 will turn
on when preset 1 is reached. When zero is reached, output 2 will
turn on and output 1 will turn off. Output 2 will remain latched on
until a manual reset occurs. Counts will continue to accumulate after preset
levels have been reached. Manual reset
✦
will turn off all outputs if activated
and the unit Resets to Preset 2.
MODE 11 OUTPUT 1 TURN OFF AT ZERO, TIMED OUTPUT 2 AT ZERO, MANUAL
RESET TO PRESET
✝
In this mode, as the unit counts from zero, output 1 will turn on
when preset 1 is reached and output 2 will turn on when preset 2 is
reached. The outputs will turn off after their respective
programmed time values have occurred. Also, when preset 2 is reached, the
unit will automatically reset the count to zero and start the cycle over.
(Output
2 will remain on until its time value has occurred.)
Manual reset
✦
will turn off
both outputs and reset the count to zero. During automatic reset, no counts
will be lost, as long as the count rate does not exceed 2,500 cps.
MODE 6 OUTPUT 1 TURN OFF AT PRESET 2, TIMED OUTPUT 2 AT PRESET 2,
AUTOMATIC RESET TO ZERO AFTER TIMED OUTPUT 2
In this mode, as the unit counts from preset 2, output 1 will turn
on when preset 1 is reached. When zero is reached, output 2 will turn
on and output 1 will turn off. Output 2 will turn off after its
programmed time value has occurred. Counts will continue to accumulate after
preset levels have been reached. When a manual reset
✦
occurs, the unit will
Reset to Preset 2. Manual reset will also turn off both outputs, if still activated.
MODE 12 OUTPUT 1 TURN OFF AT ZERO, TIMED OUTPUT 2 AT ZERO, AUTOMATIC
RESET TO PRESET 2 AT ZERO
✝
In this mode, as the unit counts from zero, output 1 will turn on
when preset 1 is reached. When preset 2 is reached, output 2 will
turn on and output 1 will turn off. Output 2 will turn off after its
programmed time value has occurred. At the end of timed output 2, the unit
will automatically Reset to Zero and start the cycle over again. During
automatic reset, no counts will be as lost as long as the count rate does not
exceed 2,500 cps. Manual reset
✦
will turn off both outputs, if turned on, and
reset the count to zero.
MODE 7 TIMED OUTPUTS AT PRESETS, AUTOMATIC RESET TO ZERO AFTER TIMED
OUTPUT 2
In this mode, as the unit counts from preset 2, output 1 will turn
on when preset 1 is reached. When zero is reached, output 2 will
turn on, output 1 will turn off, and the unit will automatically Reset
to Preset 2. Output 2 will turn off after its programmed time value has
occurred. Manual reset
✦
will turn off both outputs, if turned on, and reset the
count to preset 2. During automatic reset, no counts will be lost if the count
rate does not exceed 2,500 cps.
MODE 13 TIMED OUTPUTS AT PRESET 1 AND ZERO, AUTOMATIC RESET TO
PRESET 2 AT ZERO
✝
In this mode, as the unit counts from zero, output 1 will turn on
when preset 1 is reached and output 2 will turn on when preset 2 is
reached. The outputs will turn off after their respective
programmed time values have occurred. At the end of timed output 2, the unit
will automatically Reset to Zero and start the cycle over again. During
automatic reset, no counts will be lost, as long as the count rate does not
exceed 2,500 cps. Manual reset
✦
will turn off both outputs, if turned on, and
reset the count to zero.
MODE 8 LATCH OUTPUT AT PRESET 1 AND ZERO, MANUAL RESET TO PRESET 2
✝
In this mode, as the unit counts from preset 2, output 1 will latch
on when preset 1 is reached and output 2 will latch on when zero
is reached. When a manual reset
✦
occurs, the unit will Reset to
Preset 2 and the output, if latched on, will unlatch. Counts will continue to
register after the outputs have turned on.
MODE 9 TIMED OUTPUT AT PRESET 1 AND ZERO, MANUAL RESET TO PRESET 2
✝
In this mode, as the unit counts from preset 2, output 1 will turn
on when preset 1 is reached and output 2 will turn on when zero is
reached. The outputs will turn off after their respective
programmed time values have occurred. When a manual reset
✦
occurs, the
unit will Reset to Preset 2. Manual reset will terminate the timed outputs, if
the outputs are still activated. Counts will continue to accumulate after the
outputs have activated.
✝
When down count is desired, (such as reset to preset modes of operation)
the “UP/DN” terminal must be tied to the “COMM.” terminal.
✦
Manual reset, either by front panel reset (if enabled) or remote reset, is always
active, and will override any condition or state the counter is presently in.
In this mode, as the unit counts from preset 2, output 1 will turn
on when preset 1 is reached and output 2 will turn on when zero is
reached. The outputs will turn off after their respective programmed
time values have occurred. Also, when zero is reached, the unit will
automatically reset the count to preset 2 and start the cycle over.
(Output 2 will
remain on until its time value has occurred.)
Manual reset
✦
will turn off both
outputs, if turned on, and reset the count to preset 2. During automatic reset, no
counts will be lost, as long as the count rate does not exceed 2,500 cps.
MODE 14 OUTPUT 1 TURN OFF AT ZERO, TIMED OUTPUT 2 AT ZERO, AUTOMATIC
RESET TO PRESET 2 AFTER TIMED OUTPUT 2
✝
In this mode, as the unit counts from preset 2, output 1 will turn
on when preset 1 is reached. When zero is reached, output 2 will
turn on and output 1 will turn off. Output 2 will turn off after its
programmed time value has occurred. At the end of timed output 2, the unit
will automatically Reset to Preset 2 and start the cycle over. During automatic
reset, no counts will be lost, as long as the count rate does not exceed 2,500
cps. Manual reset
✦
will turn off both outputs, if activated, and reset the count
to preset 2.
MODE 15 TIMED OUTPUTS AT PRESET 1 AND ZERO, AUTOMATIC RESET TO
PRESET 2 AFTER TIMED OUTPUT 2
✝
In this mode, as the unit counts from preset 2, output 1 will turn
on when preset 1 is reached and output 2 will turn on when zero is
reached. The outputs will turn off after their respective
programmed time values have occurred. At the end of timed output 2, the unit
will automatically Reset to Preset 2 and start the cycle over. During automatic
reset, no counts will be lost, as long as the count rate does not exceed 2,500
cps. Manual reset
✦
will turn off either output, if turned on, and reset the count
to preset 2.
SELECTION OF INPUT SET-UP & MODES OF OPERATION
The selection of Input Set-up and Modes of Operation is accomplished by
eight DIP switches, located at the rear of the unit, in the upper right-hand
corner. DIP switches 1 to 3 are used to configure the input, and DIP switches 5
to 8 are used to determine the modes of operation. DIP switch 4 is used to
enable or disable the front panel reset button. The input set-up and reset enable
switches will be discussed first. Refer to the block diagram of the unit for the
details of count and control circuitry.
SWITCH SET-UP
S1 - SNK:
Provides a 7.8 KΩ pull-up resistor for sensors with sinking outputs.
SRC:
Provides a 3.9 KΩ pull-down resistor for sensors with sourcing
outputs.
S2 - HI FRQ:
Removes damping capacitor and allows operation up to 2.5 KHz.
Minimum count OFF times - 50 µsec.
4
LO FRQ:
Connects damping capacitor for switch contact debounce. Limits
count speed to 100 Hz. Minimum count pulses ON/OFF times - 5 msec.
S3 - HI BIAS:
Sets input trigger levels at mid-
range to accept outputs from 2-wire
proximity sensors, resistive photo-cells,
and logic pulses with full 0 to +12 V
swings. (V
IL
= 5.5 V, V
IH
= 7.5 V)
LO BIAS:
Sets input trigger levels to the
low range to accept logic pulses with 0 to 5
V swings. (V
IL
= 1.5 V, V
IH
= 3.75 V)
S4 - DIS RST:
Disables front panel reset.
EN RST:
Enables front panel reset.
POWER-UP DIAGNOSTICS
The Libra counters have internal diagnostics which will check the stored data
during power-up. When the data is saved
(power-down),
computations are
made with these values. The result of these computations is stored in the
memory to serve as a check against possible error. Then on power-up, these
same computations are repeated on the stored data. If these results do not agree
with the stored results, then a
“P”
will appear on the right side of the display.
Normal operation of the unit will continue while this
“P”
is displayed. To
remove the
“P”
from the display, press the
“E”
button. Then check
programmed values to be certain they are correct.
TO ENTER A DECIMAL POINT INTO THE
DISPLAY
FIRST:
Press the button located under the right-hand digit. At this time, the
display will
“freeze”. (The display will remain “frozen” approximately 5
seconds after release of this button,if no other buttons are pushed.)
During
the selection of decimal point, the unit will operate normally.
SECOND:
Press the button located under the desired decimal point location.
(The decimal point will appear to the right of the digit.) (This selection
cannot be made when “PGM. DIS.” is activated.)
Pressing the button located
under the right-hand digit will display no decimal point.
(This will turn off
any displayed decimal point.)
After the second button pushing operation, the
unit goes back to normal display mode.
CONNECTIONS
As depicted in the drawing
showing the rear view of the Libra
Counter, there are two terminal
blocks where all wiring connections
are made. All conductors should
meet voltage and current ratings
for each terminal. Also, cabling
should conform to appropriate
standards of good installation,
local codes and regulations. It is
recommended that power supplied
to the unit (AC or DC) be protected
by a fuse or circuit breaker. The
blocks can be removed for easy
access to the terminal screws. To
remove the block, pull from the
back of the block until it slides
clear of the terminal block shroud.
c. Connect the shield to common of the unit and leave the other end of the
shield unconnected and insulated from earth ground.
2. Never run Signal or Control cables in the same conduit or raceway with AC
power lines, conductors feeding motors, solenoids, SCR controls, and
heaters, etc. The cables should be run in metal conduit that is properly
grounded. This is especially useful in applications where cable runs are long
and portable two-way radios are used in close proximity or if the installation
is near a commercial radio transmitter.
3. Signal or Control cables within an enclosure should be routed as far away as
possible from contactors, control relays, transformers, and other noisy
components.
4. In extremely high EMI environments, the use of external EMI suppression
devices, such as ferrite suppression cores, is effective. Install them on Signal
and Control cables as close to the unit as possible. Loop the cable through the
core several times or use multiple cores on each cable for additional protection.
Install line filters on the power input cable to the unit to suppress power line
interference. Install them near the power entry point of the enclosure. The
following EMI suppression devices (or equivalent) are recommended:
Ferrite Suppression Cores for signal and control cables:
Fair-Rite # 0443167251 (RLC #FCOR0000)
TDK # ZCAT3035-1330A
Steward #28B2029-0A0
Line Filters for input power cables:
Schaffner # FN610-1/07 (RLC #LFIL0000)
Schaffner # FN670-1.8/07
Corcom #1VB3
Corcom #1VR3
Note: Reference manufacturer’s instructions when installing a line filter.
5. Long cable runs are more susceptible to EMI pickup than short cable runs.
Therefore, keep cable runs as short as possible.
6. Switching of inductive loads produces high EMI. Use of snubbers across
inductive loads suppresses EMI.
Snubbers:
RLC #SNUB0000
DC POWER AND INPUT CONNECTIONS
Terminal number 6 on TBA
(the first terminal from the left),
is the +12 VDC
input/output terminal. As an output this terminal is for sensor supply and can
provide up to 150 mA of current. As an input, an external 11 to 14 VDC supply
can be applied to this terminal to power the unit in the absence of AC power.
Terminal 5 is the common terminal which the common line from the sensor and
other inputs are connected.
(Do NOT connect relay commons or solid-state output
commons to this point.)
Terminal 4 is the count input terminal. When the signal
at this terminal is pulled low
(zero volts),
a count will be registered.
(See Count
Input and Count Rates under the Specifications section.)
Terminal number 3 is the
UP/DN terminal
(Count Direction Control).
When this terminal is at a high level,
the count direction is
“UP”.
When the terminal is grounded, the count direction
is
“DOWN”.
Terminal 2 is the Program Disable
(PGM. DIS.)
terminal. When this
terminal is at a high level, the Preset value(s) and timed output value(s) can be
changed using the front panel buttons.
(Outputs can also be tested during self-test
under this condition. See Self-Test description for further details.)
When terminal
2 is at a low level
(connected to COMM),
changing these values and testing the
outputs is no longer possible. Terminal 1 is the Remote Reset terminal. When this
terminal is at a low level
(connected to COMM),
the unit will reset, and the
outputs will turn off
(if activated).
As long as reset is low, the unit is held at reset.
DASHED LINES ARE FOR 2 PRESET UNIT ONLY
Caution:
The terminal blocks should
NOT
be removed with power applied to
the unit.
All the DC power and input connections are made to the top terminal block
labeled TBA. The AC power and output connections are made to the bottom
terminal block labeled TBB. The input connections will be discussed first,
using the drawing as a guide.
(The input connections are the same for 1 or 2 preset counters.)
EMC INSTALLATION GUIDELINES
Although this unit is designed with a high degree of immunity to
ElectroMagnetic Interference (EMI), proper installation and wiring methods
must be followed to ensure compatibility in each application. The type of the
electrical noise, source or coupling method into the unit may be different for
various installations. It should be noted that the methods listed below may not
be necessary for every unit installation. In extremely high EMI environments,
additional measures may be needed. The unit becomes more immune to EMI
with fewer I/O connections. Cable length, routing and shield termination are
very important and can mean the difference between a successful installation or
a troublesome installation. Listed below are some EMC guidelines for
successful installation in an industrial environment.
1. Use shielded (screened) cables for all Signal and Control inputs. The shield
(screen) pigtail connection should be made as short as possible. The
connection point for the shield depends somewhat upon the application.
Listed below are the recommended methods of connecting the shield, in
order of their effectiveness.
a. Connect the shield only at the panel where the unit is mounted to earth
ground (protective earth).
b. Connect the shield to earth ground at both ends of the cable, usually when
the noise source frequency is above 1 MHz.
5
AC POWER AND OUTPUT CONNECTIONS
As mentioned before, AC power and output connections are made to the
bottom terminal block, labeled TBB. Primary A.C. power is connected to
terminal 1 and 2
(marked A.C. Power, located on the left-hand side of terminal
block TBB).
For best results, the A.C. Power should be relatively
“clean”
and
within the specified ±10% variation limits. Drawing power from heavily
loaded circuits or from circuits that also power loads that cycle on and off,
should be avoided.
Terminals 3, 4, and 5 are used to connect to the output relay 1. Terminal 3 is
the normally closed contact. Terminal 4 is the normally open contact. Terminal
5 is the output relay common. Terminal 6 is an output common used for the
solid-state output(s). This terminal should NOT be used as the common for the
output relay(s) or as the common for the input or control terminals. Terminal 7
is current sinking output 1
(labeled 01-SNK.).
This internally connects to an
NPN Open Collector transistor. The remaining terminals are for the dual preset
version of the Libra counter and serve the same functions as those for the single
preset unit. Terminal 8 is current sinking output 2
(labeled 02-SNK.).
Terminal
9 is the normally closed contact of relay 2. Terminal 10 is the normally open
contact. Terminal 11 is the output relay common.
