10 chapter05 counters_fa14

Allen Bradley Counters
Counters
Chapter 05
Northampton Community College 1

Counters

Common applications of counters include keeping track of
the number of items moving past a given point, or
determining the number of times a given action occurs.
A preset counter can control an
external circuit when its counted
total matches the user-entered
preset limits.

Mechanical Counters

Programmed counters can serve
the same functions as
mechanical counters.

Every time the actuating lever is
moved or rotated, the counter
adds one number. The actuating
lever then returns automatically
to its original position. Resetting
the counter to zero is usually
done with a pushbutton located
on the unit.

Electronic Counters

Electronic counters can count up, count down, or be
combined to count up and down. They are dependent on
external sources such as parts traveling past a sensor or
actuating a limit switch for counting.
Counter
Applications
Rotary Encoder
Rotary
Encoder

Counter Counting Sequence

PLC counters are normally retentive.
 Whatever count was contained in the counter at the time of a
processor shutdown will be restored to the counter on power-up.

The counter can be reset on power-up if the reset condition
is activated at the time of power restoration.

PLC counters can be designed to count up to a preset
value or to count down to a preset value.

SLC-500/LogixPro Default Data File Types
FILE TYPE IDENTIFIER FILE
NUMBER
Output O 0
Input I 1
Status S 2
Bit B 3
Timer T 4
Counter C 5
Control R 6
Integer N 7
Float Point * F 8
* Available in SLC-5/03 OS301, OS302 & SLC-5/04 OS400, OS401 &
SLC-5/05 processors

SLC-500 User Defined Data File Types
FILE TYPE IDENTIFIER FILE NUMBER
Bit B 9 - 255
Timer T 9 - 255
Counter C 9 - 255
Control R 9 - 255
Integer N 9 - 255
Float Point * F 9 - 255
String* St 9 - 255
ASCII * A 9 - 255
File #9 has a special purpose. It is called the “Computer Interface File” (CIF) and is
used when communications is required between early AB PLCs
* Available in SLC-5/03 OS301, OS302 & SLC-5/04 OS400, OS401 & SLC-5/05
processors
Note: User defined files are not available in LogixPro

SLC-500’s/ControlLogix & LogixPro Counters

The SLC-500/Micrologix series has three counters and
ControlLogix and LogixPro Simulator has two counters:
 CTU – Count Up (SLC500’s/Micrologix, ControlLogix & LogixPro)
 CTD – Count Down (SLC500’s/Micrologix, ControlLogix & LogixPro)
 HSC – High Speed Counter
The HSC is only available in selected AB Micrologix series controllers

Counter instructions are output instructions therefore they
will always be placed against the right power rail.
 Output instructions in the SLC500 series are always placed against the right power rail
with multiple output instructions on the same rung being placed in branches.
 In the ControlLogix platform output devices are also placed against the right power rail
with multiple outputs on the same rung being branched. But the output instructions
can be placed in series on the rung.
 In LogixPro the output instruction should be placed against the right power rail and
multiple outputs on the same rung should be placed in branches. Output instructions
can be placed in series, but incorrect operation can occur.

Count Up Counters (CTU) – SLC500s & LogixPro

Counters have three instruction parameters:
Counter number
or Address of
the counter
Preset – Number of
items or events to
count before an output
occurs
Accumulator – The
current number of
counts on the counter

Counter Parameters

Counter
 The address of the counter.
 Counters are stored, by default, in data file #5 and use a file
designator of ‘C’. The valid range of counters is 0 to 255. Therefore,
for this example we will use C5:0, the first counter in the file.

Preset Value (PRE)
 The preset value is the number of counts that should occur before
the counting event is done. The value range is:
For the SLC500’s: -32,768 to 32,767.
For the LogixPro simulator: -2,147,483,648 to 2,147,483,647
For ControlLogix: -2,147,483,648 to 2,147,483,647

Accumulator Value (ACC)
 Stores the current count value of the counter. The value ranges are
the same as the Preset parameter.

Counter Memory – SLC500’s & LogixPro

Each counter, of any type, in the SLC500’s requires three
16-bit words in the counter memory.

Each counter, of an type, in the LogixPro simulator requires
three 32-bit words in the counter memory.
 Word 0 – Stores the status bits of the counter
 Word 1 – Stores the preset value
 Word 2 – Stores the accumulator value

Counter Memory Word 0, Status Bits
SLC500 & LogixPro

Counters have status bits that are stored in word 0. Some
of these bits are unique to the type of counter being
programmed and some of the bits are used for all counter
types.
 Bit 10 or Bit (UA) – Update Accumulator Bit
Select Micrologix units only
 Bit 11 or Bit (UN) – Underflow Bit
Count Down counter only
 Bit 12 or Bit (OV) – Overflow Bit
Count Up counter only
 Bit 13 or Bit (DN) – Done Bit
Count Up and Count Down counter
 Bit 14 or Bit (CD) – Count Down Bit
 Bit 15 or Bit (CU) – Count Up Bit

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Word 0 CU CD DN OV UN UA NA NA Reserved
Word 1 Preset Value (16-bit in SLC500’s, 32-bit in LogixPro)
Word 2 Accumulator Value (16-bit in SLC500’s, 32-bit in LogixPro)

Count Up (CU)
 Sets to a logic ‘1’ when the rung containing the Count Up (CTU) counter is
true, otherwise it is a logic ‘0’.

Count Down (CD)
 Sets to a logic ‘1’ when the rung containing the Count Down (CTD) counter
is true, otherwise it is a logic ‘0’.

Done (DN)
 Sets to a logic ‘1’ when the Accumulator value is greater than or equal to the
preset value (ACC ≥ PRE), otherwise it is a logic ‘0’.

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Overflow (OV) – SLC500
 Used with the Count Up counter (CTU). If the accumulator has reached the
maximum positive value of +32,767 and the counter is incremented up again,
the accumulator will wrap around to -32,768. When this “wrap around” occurs,
the Overflow (OV) bit will set to a logic ‘1’. If the Done (DN) bit is set to a ‘1’
and the counter overflows the Done (DN) bit will remain a ‘1’, even if the
accumulator is less than the preset (ACC < PRE). The counter must be reset
with the RES instruction to reset the Overflow (OV) bit to a logic ‘0’ and to clear
the Done (DN) bit.

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Overflow (OV) – LogixPro
the Overflow (OV) bit will set to a logic ‘1’, the Done (DN) bit will reset to a ‘0’
and the accumulator will contain the value of +32,768. If the CTU counter rung
continues to transition from false-to-true, the Overflow (OV) bit will remain on,
the Done (DN) bit will remain off and the accumulator will continue counting up
to a max. count of +2,147,483,647. When the max. count is achieved, the
counter will stop counting up even if the rung continues to transition from false-to-
true. The counter must be reset with the RES instruction to reset the
Overflow (OV) bit to a logic ‘0’.

Counter Memory – SLC500’s & LogixPro (lower word)
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Underflow (UN) – SLC500
 Used with the Count Down (CTD) counter. If the accumulator has reached
the minimum negative value of -32,768 and the counter is decremented
down again, the accumulator will wrap around to +32,767. When this “wrap
around” occurs, the Underflow (UN) bit will set to a logic ‘1’. If the Done (DN)
bit is set to a ‘1’ and the counter underflows the Done (DN) bit will remain a
‘1’, even if the accumulator is less than the preset (ACC < PRE). The
counter must be reset with the RES instruction to reset the Underflow (UN)
bit to a logic ‘0’ and Done (DN) bit to clear.

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Underflow (UN) – LogixPro
 Used with the Count Down counter (CTD). If the accumulator has reached
down again, the Underflow (UN) bit will set to a logic ‘1’, the Done (DN) bit
will be set to a logic ‘1’ and the accumulator will contain a value of -32,769.
If the CTD counter rung continues to transition from false-to-true, the
Underflow (UN) bit and the Done (DN) bit will remain on and the
accumulator will continue counting down to a minimum count of
-2,147,483,648. When the minimum count is achieved the counter will stop
counting down even if the rung continues to transition from false-to-true.
The counter must be reset with the RES instruction to reset the Underflow
(UN) bit to a logic ‘0’ and to clear the Done (DN) bit.

Counter Memory – Select Micrologix Processors
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Word 1 Preset Value
Word 2 Accumulator Value

Update Accumulator (UA)
 This bit is only used with the High Speed Counter (HSC). This counter is
only available in select Micrologix units. For more information on this bit,
refer to the RSLogix 500 help file.

CTU Functionality

Count Up counters count false to true rung
transitions. That is, when the rung
containing the counter transitions from false
to true, the accumulator increments up by
one count. When the rung transitions from
true to false, nothing happens at the
counter.

When the rung is true, the Count Up (CU)
bit is set to a ‘1’. When the rung is false, the
Count Up (CU) bit is reset to a ‘0’.

When the ACC ≥ PRE, the Done (DN) is set
to a ‘1’. An RES instruction is required to
reset the accumulator to zero.
Rung CU OV DN ACC
0 0 1
0 0 2
0 0 59
0 1 100
0 1 128
0 1 32,767
1 1 -32,768

Counter Addressing; SLC500’s and LogixPro

Counters, by default, are stored in data file #5 and have a
file designator of ‘C’. Therefore, counter number zero is
addressed as C5:0.

There are two main forms of addressing in AB; Bit level and
Word level. To address the status bits of a counter, use bit
level addressing as follows:
 C5:0/11 or C5:0/UN = Underflow Bit
 C5:0/12 or C5:0/OV = Overflow Bit
 C5:0/13 or C5:0/DN = Done Bit
 C5:0/14 or C5:0/CD = Count Down Bit
 C5:0/15 or C5:0/CU = Count Up Bit

Counter Adressing; SLC500’s and LogixPro

Word level addresses are used to address the value of a
16-bit word in the SLC500 series or a 32-bit word in the
LogixPro simulator. Therefore, to read the value of the
counter accumulator or preset use a word level address as
follows:
 C5:0.1 or C5:0.PRE = Value of counter zero’s preset
 C5:0.2 or C5:0.ACC = Value of counter zero’s accumulator

Almost any word in the AB memory structure can be
addressed to bit level, here is an example:
 C5:0.ACC/8
This is a bit level address that is referencing bit-8 in the accumulator
word of counter zero.

Example of Programming CTU Status Bits
SLC500 Counter shown

Count Up Counters (CTU) - ControlLogix
Counter tag name:
Ex. TotalCartons
events to count before
an output occurs
Accumulator – The
current number of
counts on the counter
ControlLogix counters function exactly like counters in the SLC500
series and LogixPro

Count Parameters - ControlLogix

Counter
 The tag name of the counter. Example: TotalCartons. The tag is
created as a Counter Data Type. The Counter data type is a
Structure because each counter uses more than one word.

Preset Value (PRE)
 The preset value is the number of counts the counter should
accumulate before an output occurs.
The valid range is: -2,147,483,648 to 2,147,483,647.

Accumulator (ACC)
 Stores the current counts of the counter.

Counter Memory - ControlLogix

Counters use a data type of type Counter.

The Counter data type is a Structure.

The counter structure consists of three, 32-bit words.

The ControlLogix counters have a total of five status bits.
Some of these bits are used only for the CTU counter, some
are used only for the CTD counter and some are shared
with the CTU and CTD counters. These bits function exactly
like the SLC500 counter status bits. The only difference is
how they are referenced.

Counter Memory - ControlLogix

Referencing counter status bits:
 Done Bit – TotalCartons.DN
 Count Up Bit – TotalCartons.CU
 Count Down Bit – TotalCartons.DN
 Overflow Bit – TotalCartons.OV
 Underflow Bit – TotalCartons.UN
The plus (+) sign is
used to expand a
structure. The minus
(-) is used to
collapse a structure
Structure
members
Data types of
the members

ControlLogix Counter
When will the OV CU bit turn on?
When will the DN bit turn on?
When When the the CTU ACC rung wraps is true. from In 2,147,483,647 this example to
for
When the ACC ≥ PRE or ACC ≥ 10,000
One scan because -2,147,483,648
of the ONS instruction

Count Down Counter – CTD

Counters have three instruction parameters (SLC500 counter
shown):
Counter number
or Address of
the counter
events to count before
an output occurs
Accumulator –
The current
number of counts
on the counter

Counter Parameters

Counter
 The address of the counter.
 Counters are stored, by default, in data file #5 and use a file
designator of ‘C’. The valid range of counters is 0 to 255. Therefore,
for this example we will use C5:1, the second counter in the file.

Preset Value (PRE)
 The preset value is the number of counts that should occur before
the counting event is done. The value range is:
 For the SLC500’s: -32,768 to 32,767.
 For the LogixPro simulator: -2,147,483,648 to 2,147,483,647
 For ControlLogix: -2,147,483,648 to 2,147,483,647

Accumulator Value (ACC)
 Stores the current count value of the counter.

Counter Memory – SLC500 & LogixPro

Each counter, of any type, in the SLC500’s requires three
16-bit words in the counter memory.

Each counter, of an type, in the LogixPro simulator requires
three 32-bit words in the counter memory.
 Word 0 – Stores the status bits of the counter
 Word 1 – Stores the preset value
 Word 2 – Stores the accumulator value

Counter Memory Word 0, Status Bits – SLC500 &
LogixPro

Counters have status bits that are stored in word 0. Some
of these bits are unique to the type of counter being
programmed and some of the bits are used for all counter
types..
 Bit 10 or Bit (UA) – Update Accumulator Bit
Select Micrologix units only
 Bit 11 or Bit (UN) – Underflow Bit
 Bit 12 or Bit (OV) – Overflow Bit
 Bit 13 or Bit (DN) – Done Bit
Count Up and Count Down counter
 Bit 14 or Bit (CD) – Count Down Bit
 Bit 15 or Bit (CU) – Count Up Bit

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Count Up (CU)
 Sets to a logic ‘1’ when the rung containing the Count Up (CTU) counter is

Count Down (CD)
 Sets a logic ‘1’ when the rung containing the Count Down (CTD) counter is

Done (DN)
 Sets to a logic ‘1’ when the Accumulator value is greater than or equal to the
preset value (ACC ≥ PRE), otherwise it is a logic ‘0’.

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Overflow (OV) – SLC500
the accumulator will wrap around to -32,768. When this “wrap around” occurs,
the Overflow (OV) bit will set to a logic ‘1’. If the Done (DN) bit is set to a ‘1’
and the counter overflows the Done (DN) bit will remain a ‘1’, even if the
accumulator is less than the preset (ACC < PRE). The counter must be reset
with the RES instruction to reset the Overflow (OV) bit to a logic ‘0’ and to clear
the Done (DN) bit.

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Overflow (OV) – LogixPro
the Overflow (OV) bit will set to a logic ‘1’, the Done (DN) bit will reset to a ‘0’
and the accumulator will contain the value of +32,768. If the CTU counter rung
continues to transition from false-to-true, the Overflow (OV) bit will remain on,
the Done (DN) bit will remain off and the accumulator will continue counting up
to a max. count of +2,147,483,647. When the max. count is achieved, the
counter will stop counting up even if the rung continues to transition from false-to-
true. The counter must be reset with the RES instruction to reset the
Overflow (OV) bit to a logic ‘0’.

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Underflow (UN) – SLC500
 Used with the Count Down (CTD) counter. If the accumulator has reached
down again, the accumulator will wrap around to +32,767. When this “wrap
around” occurs, the Underflow (UN) bit will set to a logic ‘1’. If the Done (DN)
bit is set to a ‘1’ and the counter underflows the Done (DN) bit will remain a
‘1’, even if the accumulator is less than the preset (ACC < PRE). The
counter must be reset with the RES instruction to reset the Underflow (UN)
bit to a logic ‘0’ and Done (DN) bit to clear.

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Underflow (UN) – LogixPro
 Used with the Count Down counter (CTD). If the accumulator has reached
down again, the Underflow (UN) bit will set to a logic ‘1’, the Done (DN) bit
will be set to a logic ‘1’ and the accumulator will contain a value of -32,769.
If the CTD counter rung continues to transition from false-to-true, the
Underflow (UN) bit and the Done (DN) bit will remain on and the
accumulator will continue counting down to a minimum count of -
2,147,483,648. When the minimum count is achieved the counter will stop
counting down even if the rung continues to transition from false-to-true.
The counter must be reset with the RES instruction to reset the Underflow
(UN) bit to a logic ‘0’ and to clear the Done (DN) bit.

Counter Memory – Select Micrologix Processors
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Word 1 Preset Value
Word 2 Accumulator Value

Update Accumulator (UA)
 This bit is only used with the High Speed Counter (HSC). This counter is
only available select Micrologix units. For more information on this bit, refer
to the RSLogix help file.

CTD Functionality
Reset the CTD
counter.
Field device is NC
RES_CTD_CNTR
I:1
10
Count DOWN counter
CTD_COUNTER
C5:1

0006
Count Down counters count false to true
rung transitions. That is, when the rung
containing the counter transitions from false
to true, the accumulator decrements down
by one count. When the rung transitions
from true to false, nothing happens at the
counter.

When the rung is true, the Count Down
(CD) bit is set to a ‘1’. When the rung is
false, the Count Down (CD) bit is reset to a
‘0’.

When the ACC ≥ PRE, the Done (DN) is set
to a ‘1’. An RES instruction is required to
reset the accumulator to zero.
RES
Rung CD UN DN ACC
0 1 -1
0 1 -36
0 1 -50
0 0 -51
0 0 -32,768
1 0 32,767


Counters, by default, are stored in data file #5 and the file
designator is ‘C’. Therefore, counter number one is
addressed as C5:1

There are two main forms of addressing in AB; Bit level and
Word level. To address the status bits of a counter use bit
level addressing as follows:
 C5:1/11 or C5:1/UN = Underflow Bit
 C5:1/12 or C5:1/OV = Overflow Bit
 C5:1/13 or C5:1/DN = Done Bit
 C5:1/14 or C5:1/CD = Count Down Bit
 C5:1/15 or C5:1/CU = Count Up Bit


Word level addresses are used to address the value of a
16-bit word in the SLC500’s or a 32-bit word in the LogixPro
simulator. Therefore, to read the value of the counter
accumulator or preset use a word level address as follows:
 C5:1.1 or C5:1.PRE = Value of counter one’s preset
 C5:1.2 or C5:1.ACC = Value of counter one’s accumulator

Almost any word in the AB memory structure can be
addressed to bit level, here is an example:
 C5:1.ACC/8
This is a bit level address that is referencing bit-8 in the accumulator
word of counter one.

ControlLogix CTD Counter

The ControlLogix CTD counter functions exactly like the
SLC500 series and LogixPro CTD counter.

It uses a Counter data type. The data type is a structure.

Counter Examples

Parts Counting Program

Counter C5:2 counts the total
number of parts coming off an
assembly line for final packaging.

Each package must contain 10-
parts.

When 10-parts are detected,
counter C5:1 sets bit B3:0/1 to
initiate the box closing sequence.

Counter C5:3 counts the total
number of packages filled per
day.

A pushbutton is used to restart
the total part and package count
to zero, daily.

Part Counting Program
SLC500 Counters shown
Program continued on next slide

Part Counting Program

Conveyor Motor Circuit

This circuit will use a oneshot for
reset and another oneshot to
prevent proximity switch chatter.

Sequential task:
 The start pushbutton is pressed
to start the conveyor motor.
 Cases move pass the proximity
switch and increment the
counters accumulated value.
 After a count of 50, the conveyor
motor stops automatically and
the counter’s accumulated value
is reset to zero.
 The conveyor motor can be
stopped or started manually at
any time without loss of the
accumulated counts.
Proximity
switch
Case
Conveyor motor
Start/Stop station
Count reset
button

Conveyor Motor Program
ControlLogix ladder shown

Alarm Monitor Program

The alarm is triggered by the closing of liquid level switch LS1.

The alarm light will flash whenever the alarm condition is triggered and
has not been acknowledged, even if the alarm condition clears in the
meantime.

The alarm is acknowledged by closing selector switch SS1.

The alarm light will operate in the steady mode when the alarm trigger
condition exists but has been acknowledged.

Alarm Monitor Program
LogixPro Timers & Counters shown

Parking Garage Counter Program

As a car enters the parking garage it triggers an up counter and
increments the accumulator by one count.

As a car leaves the parking garage it triggers a down counter and
decrements the accumulator by one count.

The up and down counters will use the same address. Since the
counters have the same address the accumulated value is the same for
both counters.

Whenever the accumulator value is equal to the preset value the counter
output is energized to light the “Lot Full” sign.

Parking Garage Counter Program

In Process Monitoring System

Before start-up, the system is completely empty of parts and the counter
is reset manually to zero.

When the operation begins, raw parts move through the in-feed sensor
with each part generating an up count.

After processing, finished parts appearing at the out-feed sensor
generate down counts, so the accumulated count of the counter
continuously indicates the number of in-process parts.

In Process Monitoring System
ControlLogix Counters shown

More Counter Information

Counter Speed

The maximum speed of
transitions that can be counted is
determined by the processor
scan time. Any counter input
signal must be fixed for one scan
time to be counted reliably.

If the input changes faster than
one scan cycle, the count value
will become unreliable because
counts will be missed. When this
is the case a high-speed counter
instruction or module is required.

Cascading Counters

Depending upon the application,
it might be necessary to count
events that exceed the maximum
number allowable per counter
instruction. One way of
accomplishing count values that
exceed the maximum allowed is
by interconnection, or cascading,
counters.

Counting Beyond the Maximum Count – SLC500
How many counts occur before O:5/13 energizes?
C5:1.ACC + C5:3.ACC = 32,767 + 300 = 33,067

Optical Encoder

An optical encoder creates a
series of square waves as its
shaft is rotated.

The encoder disk interrupts the
light as the encoder shaft is
rotated to produce a square
wave output waveform.

Optical Encoder

The number of square waves
obtained from the output of the
encoder can be made to
correspond to the mechanical
movement that has occurred.

To divide a shaft revolution into
1,024 parts, an encoder could be
selected to supply at least 1,024
pulses (square wave cycles) per
revolution. By using a counter to
count those cycles it can be
determined how far the shaft has
rotated.

A special high speed counting
module might be required for
these types of applications
1024
0

More Counter Examples

Cutting Material to a Specific Size

The material is advanced for a specific distance and measured by
encoder pulses to determine the correct length for cutting.

Counter Used for Length Measurement

Count input pulses are generated by the magnetic sensor mounted such
that it detects passing teeth on a conveyor drive sprocket. If 10-teeth per
foot of conveyor motion pass the sensor, the accumulated count of the
counter would indicate feet in tenths.

The photoelectric sensor monitors a reference point on the conveyor.
When activated, it prevents the unit from counting thus permitting the
counter to accumulate counts only when bar stock is moving.

Combining Counter and Timer Functions
Automatic Stacking Process

When the start pushbutton is
pressed conveyor M1 begins
running.

After 15-plates have been
stacked, conveyor M1 stops and
conveyor M2 begins running.

After conveyor M2 has been
operated for 5-seconds it stops
and the sequence is repeated
automatically.

The done bit of the timer resets
the timer and the counter and
provides a momentary pulse to
automatically restart conveyor
M1 Can you see anything wrong with this process?
If so, what is wrong?
The biggest problem with this
process is that timers should never
be used for control. M2 will run for
5-second, but what if something
happens that the complete stack
only moves to a point where the
light sensors are no longer sensing
them? There really should be a
sensor sensing when the complete
stack is clear of the stacker.

Automatic Stacking Program

Motor Lock-Out Program

Designed to prevent a machine
operator from starting a motor
that has tripped off more than 5-
times in an hour.

The normally open (OL) relay
contact momentarily closes each
time an overload current is
sensed.

Every time the motor stops due
to an overload condition, the
motor start circuit is locked out
for 5-minutes.

If the motor trips off more than 5-
times in an hour, the motor start
circuit is permanently locked out
and cannot be started until the
reset button is actuated.

Motor Lock-Out Program

10 chapter05 counters_fa14

More Related Content

Similar to 10 chapter05 counters_fa14 (20)

More from John Todora (20)

Recently uploaded (20)

10 chapter05 counters_fa14

Editor's Notes