What Are Elapsed Time Meters?
Elapsed Time Meters (ETMs) are precision instruments that record the total operational time of machines or systems, providing crucial data for industrial applications. These devices, also known as hour meters or run time accumulators, offer readouts in various units such as seconds, minutes, hours, or days. ETMs come in both electronic and electromechanical forms, with electronic versions often featuring digital displays and the ability to record up to 99,999 hours of continuous use. Key features of modern ETMs include non-volatile memory for data retention without power, versatile voltage operations, and options for resettable or non-resettable counts, making them indispensable tools for tracking equipment usage and maintaining operational efficiency.
Elapsed Time Meters VS Hours Meters
Hour meters and elapsed time meters are often used interchangeably, but there are subtle differences in their functionality and applications:
- Hour meters typically measure time in hours and fractions of hours, usually displaying up to 99999.9 hours. They are commonly used to track runtime for maintenance scheduling on equipment like generators, pumps, and industrial machinery.
- Elapsed time meters (ETMs) can measure time in various units, including seconds, minutes, hours, or even days. They offer more flexibility for tracking shorter or longer time intervals, making them suitable for a wider range of applications, from short-term process monitoring to long-term equipment usage tracking.
While both types of meters serve similar purposes, ETMs generally provide more versatility. For instance, an ETM might be used to measure production cycle times in minutes for manufacturing processes, while an hour meter would be more appropriate for tracking total engine runtime on heavy equipment. The choice between the two often depends on the specific needs of the application and the desired level of precision in time measurement.
Elapsed Time Meter Operation
Elapsed Time Meters (ETMs) operate by continuously measuring and recording the duration of equipment operation. Electronic ETMs typically use a quartz crystal oscillator as an accurate time base, counting pulses to measure elapsed time. When power is applied to the ETM, it begins accumulating time, storing the data in non-volatile memory to prevent loss during power interruptions.
Mechanical ETMs often employ a synchronous motor connected to a gear train, which drives a set of number wheels to display the accumulated time. These devices are usually wired in parallel with the equipment being monitored, activating when the equipment is powered on. Some advanced ETMs offer additional features such as:
- Digital communication options for network setup and interrogation
- Multiple display formats (e.g., hours:minutes:seconds or days)
- Rechargeable battery backup to retain counts during power outages
- Integration with other functions like event counting or voltage monitoring
ETMs are designed to be tamper-resistant, with many models offering no reset capability to ensure accurate lifetime tracking of equipment usage.
Types of Elapsed Time Meters
Two main categories of Elapsed Time Meters are widely used in industrial settings:
- Electronic ETMs: Compact devices with digital displays, typically LCD, capable of recording up to 99,999 hours of continuous use. They feature non-volatile memory, operate on various voltage ranges (usually 5-28 VDC), and offer options for resettable or non-resettable counts. Popular models include the ENM T1100 Series and Lascar EMC1500.
- Electromechanical ETMs: These utilize mechanical components to display accumulated time, often featuring a wheel-type indicator visible even without power. They are commonly powered by AC mains or low-voltage sources and support manual reset options. The Weschler GH/BH series is a well-known example in this category.
Applications of Elapsed Time Meters
Elapsed Time Meters serve various critical functions across industries:
- Industrial Monitoring: ETMs track operational hours of machinery, facilitating maintenance scheduling and warranty verification.
- Equipment Usage Tracking: Businesses can monitor frequency of equipment use, aiding in resource management and optimization.
- Maintenance Scheduling: By providing accurate run-time data, ETMs enable companies to plan preventive maintenance before failures occur, reducing downtime and extending equipment lifespan.
- Warranty Verification: These devices offer proof of usage duration, which is essential for processing warranty claims on industrial equipment.
In specific applications, ETMs are used to record total pump run time in control systems, such as the SJE Rhombus Elapsed Time Meter with piggy-back plug, which integrates seamlessly with plugger-style control panels.
Choosing the Right Elapsed Time Meter
When selecting an Elapsed Time Meter (ETM) for your specific application, several key factors should be considered to ensure optimal performance and compatibility:
- Power Source: Determine whether your application requires an AC or DC powered ETM.
- Display Type: Choose between digital and analog displays based on your readability preferences and environmental conditions.
- Measurement Range: Consider the expected operational lifespan of your equipment.
- Resolution: Determine the level of precision required for your time measurements.
- Environmental Factors: Opt for ruggedized models designed for industrial environments.
- Additional Features: Consider ETMs with extra functionalities that may benefit your application.
- Certification and Compliance: Ensure the chosen ETM meets any industry-specific standards or certifications required for your application.
Installation and Setup of Elapsed Time Meters
Installing and setting up an Elapsed Time Meter (ETM) is generally straightforward, but proper installation is crucial for accurate time tracking. For most ETMs, the process involves connecting the device to the power source of the equipment being monitored. In the case of generators or vehicles, the ETM is typically wired to the ignition system.
For spark plug-based engines, installation often involves wrapping the ETM’s wire around the spark plug wire, approximately 4 centimeters from the boot. The meter itself can be mounted on a convenient surface using screws or adhesive backing, depending on the model.
Wiring and Connectivity Guidelines
When installing an Elapsed Time Meter (ETM), proper wiring and connectivity are crucial for accurate operation. Most ETMs connect directly to the power source of the equipment being monitored. For AC-powered devices, ETMs typically have screw terminals or wire leads for connection to 120V, 240V, or 480V power supplies. DC-powered meters often operate on voltages ranging from 5-28VDC.
For engine-based applications, such as generators, the ETM’s sensing wire is usually wrapped around the spark plug wire, approximately 4 centimeters from the boot. When installing panel-mounted ETMs, ensure proper sealing to maintain the enclosure’s environmental rating.
