Digital Length Meter

The Digital Length Meter is a six-digit industrial
measuring instrument used to calculate and display the running length of
wire, cable, fabric, plastic film, paper, rubber strip, pipe, rope, sheet,
conveyor material and other continuously moving products.

The instrument works like a standard pulse counter with an additional
programmable divider. It receives pulses from a proximity sensor,
photoelectric sensor, limit switch, measuring-wheel arrangement or compatible
single-channel encoder. The incoming pulse count is divided by the selected
calibration value, and the resulting length is shown on the six-digit
seven-segment LED display.

For example, when a measuring system produces 50 pulses for every metre of
material, the divider is set to 50. The display increases by one metre after
every 50 valid input pulses.

Industrial Digital Length Meter

The Digital Length Meter is designed for machines where
length must be calculated from repetitive mechanical movement. A measuring
wheel, roller, gear, sprocket or rotating shaft produces a fixed number of
electrical pulses for a known length of material.

The meter counts every valid sensor pulse internally. When the accumulated
pulse count becomes equal to the programmed divider value, the main
six-digit display increases by one unit. The internal pulse accumulator then
starts counting towards the next displayed unit.

When the divider represents pulses per metre, the displayed value represents
metres. The same operating principle can be configured for centimetres,
feet, yards, pieces or another engineering unit when the mechanical
arrangement and divider are calculated accordingly.

Actual Working Principle from the Embedded Firmware

The standard embedded program uses one pulse input and one internal divider.
Each valid input pulse increases the internal pulse accumulator. The displayed
total does not increase on every pulse unless the divider is set to one.

The operating relationship is:

Displayed length = Total valid input pulses ÷ Programmed divider

Only complete divider groups are added to the main display. Remaining pulses
are retained internally and used during the next measuring cycle.

Example with Divider Set to 10

Digital Length Meter Operation Sequence

1. Switch ON the 220 VAC supply to the meter.
2. The six-digit LED display restores the previously saved length value.
3. Material movement rotates the connected measuring wheel, roller or shaft.
4. The proximity sensor, photo sensor, limit switch or encoder generates
   electrical pulses.
5. Every valid pulse increases the internal pulse accumulator.
6. The meter compares the accumulated pulses with the programmed divider.
7. When the pulse accumulator reaches the divider value, the displayed length
   increases by one.
8. The pulse accumulator resets for the next displayed length unit.
9. This process continues while the material moves through the machine.
10. During power failure, the displayed length and unfinished pulse remainder
    are stored in non-volatile memory.
11. When power returns, measurement continues from the previously stored value.

Main Features of Digital Length Meter

• Six-digit industrial length display
• Bright red seven-segment LED indication
• Visible measuring range from 000000 to 999999
• Single-channel up-counting operation
• Programmable pulse-divider function
• Divider range from 1 to 255 in the standard firmware
• Counts pulses from a compatible external sensor
• Suitable for proximity-sensor input arrangements
• Suitable for limit-switch pulse inputs
• Compatible with suitable photoelectric sensors
• Compatible with suitable single-channel encoders
• Programmable through front-panel switches
• SET button for calibration-value adjustment
• UP button for increasing the divider value
• DN button for decreasing the divider value
• DN key works as total RESET during normal operation
• Power-failure retention of displayed length
• Power-failure retention of partial pulse count
• Compact 96 × 48 mm front-panel size
• Industrial PP or ABS enclosure
• 220 VAC operating supply
• No battery required for value retention
• Suitable for continuous industrial measurement

Technical Specifications

The following specifications apply to the standard
Digital Length Meter represented by the supplied embedded
program. Sensor voltage, sensor output and maximum practical pulse rate must
be matched to the meter input circuit before installation.

How to Set the Divider Value

The divider determines how many sensor pulses are required to increase the
main display by one length unit.

1. Switch ON the Digital Length Meter.
2. Press the SET button once to enter divider-setting mode.
3. The currently programmed divider value appears on the display.
4. Press the UP button to increase the divider.
5. Press the DN button to decrease the divider.
6. The divider cannot be reduced below one.
7. Set the required value between 1 and 255.
8. Release the buttons and allow the setting mode to close after the
   inactivity period.
9. The changed divider is stored in non-volatile memory.
10. The main display then returns to the measured-length value.

During normal operation, the UP button may be used to view the current
divider value without resetting the measured total.

How to Reset the Displayed Length

1. Confirm that the meter is in normal measuring mode.
2. Record the existing reading before resetting when production records are
   required.
3. Press the DN/RESET button.
4. The displayed length returns to 000000.
5. Release the button before restarting the machine.

The same DN button is used for reducing the divider when the meter is in
setting mode. In normal measuring mode, it resets the displayed total.

How to Calculate the Divider

The most reliable method is to determine how many sensor pulses are produced
for one metre of material.

Divider = Number of sensor pulses produced per metre

Example 1: Measuring Wheel and Encoder

A measuring wheel has a circumference of 0.50 metre and the connected sensor
generates 20 pulses for every complete wheel revolution.

One metre requires two wheel revolutions:

2 revolutions × 20 pulses = 40 pulses per metre

Set the divider to 40. The display will increase by one
metre after every 40 valid input pulses.

Example 2: One Pulse per Wheel Revolution

A measuring wheel has a circumference of 0.25 metre and produces one pulse
for every revolution.

Four revolutions are required for one metre:

1 metre ÷ 0.25 metre = 4 pulses per metre

Set the divider to 4.

Example 3: Direct Calibration

Run exactly 10 metres of material and count 600 raw sensor pulses during the
test.

Divider = 600 pulses ÷ 10 metres = 60

Set the divider to 60.

Divider Range Limitation

The standard embedded program stores the divider as an eight-bit value.
Therefore, the adjustable divider range is from 1 to 255.

When the measuring arrangement produces more than 255 pulses per metre,
one of the following methods should be considered:

• Use a lower-resolution encoder
• Reduce the number of sensing teeth or targets
• Use a larger measuring-wheel circumference
• Use mechanical pulse reduction
• Request customised firmware with a larger divider range

Suitable Length-Sensing Arrangements

Measuring Wheel with Proximity Sensor

A metal target or toothed wheel rotates with the measuring roller. The
proximity sensor generates one pulse whenever a target passes the sensing
face.

Measuring Wheel with Rotary Encoder

A single encoder output produces multiple pulses per revolution. The
divider converts the encoder pulses into displayed metres or another
selected unit.

Photoelectric Sensor with Printed Marks

A photoelectric sensor detects regular marks, holes or reflective labels on
the moving material or measuring wheel.

Limit Switch with Mechanical Cam

A rotating cam operates the limit switch once or several times per
revolution. This arrangement is suitable for slower machines where
mechanical contact wear is acceptable.

Applications of Digital Length Meter

• Wire drawing machines:
  Measuring the length of drawn wire collected on drums or coils.
• Cable manufacturing:
  Measuring electrical cable during extrusion, rewinding and packing.
• Textile machinery:
  Measuring fabric, cloth, ribbon, webbing and technical textiles.
• Paper industries:
  Measuring paper rolls, sheets and continuous paper webs.
• Plastic-film plants:
  Measuring film during extrusion, printing, lamination and rewinding.
• Rubber industries:
  Measuring rubber strip, profiles, sheet and extruded products.
• Pipe and hose manufacturing:
  Measuring plastic pipe, rubber hose, conduit and tubing.
• Rope and twine manufacturing:
  Measuring rope, cord, thread and industrial twine.
• Printing machines:
  Monitoring the running length of paper, film and label material.
• Lamination machines:
  Measuring the total processed length of laminated material.
• Coating machines:
  Recording the length of coated sheet, web or film.
• Cut-to-length machines:
  Monitoring feed length before manual or automatic cutting.
• Conveyor systems:
  Estimating conveyor travel from roller or shaft pulses.
• Packaging machines:
  Measuring packing film, wrapping material and product web length.
• Metal strip processing:
  Measuring coil strip during rolling, slitting and rewinding.

Benefits of Digital Length Meter

• Provides continuous six-digit length indication
• Converts ordinary sensor pulses into engineering length units
• Adjustable for different wheel diameters and sensor arrangements
• Reduces dependence on manual length measurement
• Improves roll, coil and batch production records
• Helps reduce short-length and excess-length dispatch errors
• Retains the measured value during power failure
• Retains incomplete divider pulses during power interruption
• Simple three-button front-panel operation
• Bright display visible from the machine operating position
• Compact panel-mounted design
• Suitable for existing and new production machines
• Works with different compatible pulse-generating sensors
• Custom calibration possible for each machine

Installation Guidelines

1. Install the meter inside a clean and dry electrical control panel.
2. Protect the display and electronics from water, oil, dust and corrosive fumes.
3. Mount the measuring wheel so that it remains in firm contact with the material.
4. Avoid excessive wheel pressure that could deform or stretch the product.
5. Prevent the wheel from slipping on smooth, oily or wet material.
6. Align the sensor correctly with the rotating target or encoder.
7. Maintain the sensing gap recommended for the selected proximity sensor.
8. Install the sensor bracket firmly to prevent movement caused by vibration.
9. Keep signal wiring away from motors, heaters, contactors and VFD cables.
10. Use shielded cable when electrical interference is present.
11. Connect the cable shield according to the control-panel earthing practice.
12. Confirm sensor voltage and output compatibility before connection.
13. Provide a suitable fuse or MCB for the 220 VAC supply.
14. Provide proper electrical earthing to the control panel.
15. Complete field calibration using a known material length.

Length Calibration Procedure

1. Measure an accurate reference length, preferably 10 metres or more.
2. Ensure the measuring wheel is clean and correctly pressed against the material.
3. Reset the Digital Length Meter to 000000.
4. Enter the initially calculated divider value.
5. Run the complete reference length through the machine.
6. Compare the meter reading with the actual reference length.
7. When the displayed length is higher than the actual length, increase the divider.
8. When the displayed length is lower than the actual length, decrease the divider.
9. Use the following formula for a corrected divider:

New divider = Existing divider × Displayed length ÷ Actual length

Round the calculated result to the nearest available whole-number divider
and repeat the calibration test.

Factors Affecting Length Accuracy

The electronic divider counts valid pulses consistently, but total system
accuracy depends mainly on the mechanical measuring arrangement.

• Incorrect measuring-wheel circumference
• Measuring-wheel wear
• Wheel slip on the product
• Oil, dust or water on the material
• Improper wheel pressure
• Material stretching under tension
• Loose sensor or encoder coupling
• Missed pulses at excessive speed
• Electrical noise creating false pulses
• Incorrect divider setting
• Variation in product thickness
• Mechanical vibration or roller bounce

Troubleshooting Digital Length Meter

Maintenance and Safety Precautions

• Switch OFF the 220 VAC supply before changing wiring.
• Do not touch live terminals while the instrument is energised.
• Use a suitable fuse or miniature circuit breaker.
• Inspect the measuring wheel for wear and contamination.
• Clean the wheel regularly to prevent measurement slip.
• Check sensor mounting and sensing gap periodically.
• Inspect the encoder coupling for looseness.
• Protect the pulse cable from cuts, heat and chemical exposure.
• Do not route signal and mains cables in the same conduit.
• Recalibrate after changing the wheel, sensor, encoder or gearing.
• Record the reading before pressing the reset button.
• Do not apply an incompatible voltage to the pulse-input terminal.
• Do not use this meter as a certified commercial billing instrument.
• Use a certified measuring system where legal metrology approval is required.

Digital Length Meter in Delhi NCR

UMA Industries supplies Digital Length Meter units,
proximity sensors, pulse counters and customised measuring instruments to
wire manufacturers, cable plants, textile industries, plastic processors,
machine builders, automation companies and OEM panel manufacturers
throughout Delhi NCR and nearby industrial regions.

Industrial Areas in Delhi

• Okhla Industrial Area
• Bawana Industrial Area
• Narela Industrial Area
• Naraina Industrial Area
• Mayapuri Industrial Area
• Wazirpur Industrial Area
• Mundka Industrial Area
• Patparganj Industrial Area
• Jhilmil Industrial Area
• Badli Industrial Area

Faridabad and Ballabgarh

• DLF Industrial Area
• New Industrial Township
• Sector 24 Industrial Area
• Sector 25 Industrial Area
• Sector 27A Industrial Area
• Sector 58 Industrial Area
• Sector 59 Industrial Area
• IMT Faridabad
• Ballabgarh Industrial Area
• Prithla Industrial Area

Noida and Greater Noida

• Noida Phase I Industrial Area
• Noida Phase II Industrial Area
• Noida Sectors 57 to 65
• Noida Sectors 80 to 85
• Surajpur Industrial Area
• Kasna Industrial Area
• Ecotech I Industrial Area
• Ecotech II Industrial Area
• Ecotech III Industrial Area

Gurugram, Manesar and Dharuhera

• Udyog Vihar
• IMT Manesar
• Sector 18 Industrial Area
• Sector 37 Industrial Area
• Kadipur Industrial Area
• Binola Industrial Area
• Dharuhera Industrial Area
• Bawal Industrial Area

Ghaziabad and Sahibabad

• Sahibabad Industrial Area
• Bulandshahr Road Industrial Area
• Meerut Road Industrial Area
• South Side GT Road Industrial Area
• Tronica City
• Loni Industrial Area
• Dasna Industrial Area

Other Nearby Industrial Locations

• Bahadurgarh Industrial Area
• Kundli Industrial Area
• Rai Industrial Estate
• Sonipat Industrial Area
• Panipat Industrial Area
• Bhiwadi Industrial Area
• Khushkhera Industrial Area
• Tapukara Industrial Area
• Neemrana Industrial Area

Related Counter and Measuring Products

• 
  Digital Length Counter
  
  – Six-digit divider counter for measuring wire, cable, fabric, film and
  other moving materials.
• 
  Digital Counter
  
  – Six-digit pulse counter for machines, sensors, production and event counting.
• 
  Digital Batch Counter
  
  – Production counter with programmable batch-count functions.
• 
  Counter Totalizer
  
  – Digital counter for current and cumulative production records.
• 
  Digital Timers and Logic Controllers
  
  – Industrial timers, hour meters and customised control instruments.
• 
  UMA Industries Industrial Instruments
  
  – Complete range of counters, sensors, controllers and process instruments.

External Technical Reference

Rotary encoders convert rotational movement into electrical pulse signals
that can be counted by an industrial meter. Additional technical information
about encoder operation, pulse resolution and selection is available from the

OMRON technical guide for rotary encoders
.

Frequently Asked Questions

Order Digital Length Meter

Contact UMA Industries to order a Digital Length Meter for
wire, cable, textile, paper, plastic film, rubber, pipe, rope, printing,
coating, lamination and cut-to-length machines.

Share the material type, measuring-wheel diameter, pulses per revolution,
required unit, expected machine speed and sensor details. UMA Industries can
recommend a suitable divider setting, pulse sensor and measuring-wheel
arrangement.