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Measuring Pulse Length
Measuring Pulse Length
This SOP provides step-by-step instructions for accurately measuring pulse length on a chain or belt conveyor.
Required Materials
Required Materials
● Measuring tape (resistant to chemical exposure)
● Chemical-resistant marking tool (e.g., wax crayon or paint)
● Stopwatch or timer
● Calculator (optional)
Safety Precautions
● Avoid performing measurements when vehicles are on the conveyor, if
possible.
● Wear appropriate PPE as applicable.
Procedure
Procedure
Step 1: Measure and Mark the Distance
1. Use a measuring tape to measure a 15-foot section on the surface.
2. Mark both ends of the measured section using a chemical-resistant marking tool (e.g., wax crayon or chemical-resistant paint) to ensure visibility in the working environment.
3. Verify the markings are clear and easily visible.
Step 2: Measure Roller Travel Time
1. Request a roller using a manual request such as “Extra Roller”. If measuring on a belt conveyor, use one of the tabs that pushes the vehicle.
2. Use a stopwatch to measure the time (in seconds) to travel the 15-foot distance.
3. Record the time.
4. Repeat this step at least three times to ensure accuracy.
Step 3: Calculate Roller Speed
1. For each recorded time, calculate the roller speed using the formula:
Speed (ft/sec) = Distance (15 feet) ÷ Time (seconds)
2. Record the speed for each trial.
Step 4: Calculate the Average Speed
1. Add up all the recorded speed values from Step 3.
2. Divide the total by the number of trials (at least 3) to determine the average speed:
Average Speed = (Sum of all speeds) ÷ (Number of trials)
3. Record the final average speed.
Step 5: Convert Conveyor Speed to Inches per Minute
1. Convert the average speed from feet per second to inches per minute using the formula:
Inches per minute = (Average Speed × 12 inches) × 60 seconds
2. Example calculation:
○ If the average speed is 0.84 feet/sec, then:
(0.84 × 12) × 60 = 604.8 inches/min
3. Record the conveyor speed in inches per minute if needed.
Step 6: Collect Average Pulse Time from TunnelWatch
1. Log in to the TunnelWatch website using your credentials.
2. Navigate to the 'Operations' page.
3. Select the 'Pulse Graph' button.
4. Locate and notate the average pulse time as displayed.
a. If there are consistent, large swings in average pulse time and/or lost pulses,
take note and notify your AD, RD, and facilities team.
Step 7: Calculate Pulses per Minute
1. Use the following formula to determine the number of pulses per minute:
Pulses per minute = 60 ÷ Average Pulse Time (seconds)
2. Example calculation:
○ If the average pulse time is 1.45 seconds, then:
60 ÷ 1.45 ≈ 41.38 pulses/min
3. Record the calculated pulses per minute.
Step 8: Calculate Inches per Pulse
1. Use the following formula to determine inches per pulse:
Inches per pulse = Inches per minute ÷ Pulses per minute
2. Example calculation:
○ If the conveyor speed is 604.8 inches/min and there are 41.38 pulses per minute, then:
604.8 ÷ 41.38 ≈ 14.62 inches/pulse
3. Record the calculated inches per pulse.
Step 9: Enter Pulse Length into TunnelWatch
1. Navigate to the 'Setup' page in TunnelWatch.
2. Select 'Tunnel Related Inputs' from the menu.
*Note the current pulse length setting and current speed the conveyor is travelling on the TCS Production screen. If these are not similar to the new calculation do not enter the new pulse information in step 3 until you are ready to remeasure and retime all equipment.
3. Enter the calculated inches per pulse into the 'Average Pulse Length' field.
*Access to this setting is restricted, contact an AD, RD, or Facilities team member to enter the data.
4. Click 'Save Changes' to apply the update.
5. Invoke the changes as required.
Step 10: Monitoring and adjusting the pulse
Once the pulse length has been set note the change in the ft/sec on the TunnelWatch screen. Write this down on the Tunnel Operations guide that should be hanging near the TCS indicating the correct speed for the conveyor if simulated pulse must be used in the future for an emergency.
Retime any equipment that is not turning on/off as expected by performing a remeasure of that equipment from the tunnel entrance.
Documentation and Reporting
● Ensure all measurements, calculations, and results are documented for review
if requested.
● Report any inconsistencies or irregularities to your AD, RD, and facilities team.
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