Welcome to our comprehensive guide on clock systems, where we delve into the evolution of timekeeping technologies from past to present. In this guide, you’ll discover the various types of clocks, including Wi-Fi, RF wireless, wired, and PoE systems, along with insights into when digital or analog clocks are most effectively used. Whether you’re looking to understand the basics or explore our range of products, this guide is designed to educate and assist you in finding the perfect clock system solutions.
Hard-wired clock systems are comprised of a Master Clock with multiple Secondary Clocks. The Master Clock is typically a controller box that also can control bells, tones, or other devices for schools. The Secondary clocks receive power and reset information from the Master Clock. Clocks can be analog or digital type.
Dominating the market from the 1930s into the 21st century, our synchronous motor clock system is the undisputed king of master clock systems. Renowned for its accuracy and reliability, many National Time and Signal systems have been in constant operation for over 40 years. While heavy-duty motors and solenoids have evolved into microprocessors and electronics, National Time continues to have you covered. Our Spectrum Series clocks can seamlessly coexist with your legacy clocks on the same circuit, ensuring ongoing support for your investment. Digital clocks are also capable of sharing the same circuit.
These are 3-wire systems that comprise of Common, Run, and Reset wires. Just as the names imply, the Run wire powers the motors. The Reset is pulsed by the master clock to synchronize the clocks. An example reset pulse would be: 25 seconds each hour, 25 minutes every 6:00 for National Time clocks.
In 1990, National Time invented a clock system that could operate on only 2-wires. They devised a method of powering the clocks as well as sending time information over the same wires. The protocol used was simple enough to allow relay contacts, available on most master clocks, to transmit this data to the clocks. When the clocks received this time information from the master clock, they could immediately advance to the correct time without waiting for the customary 12-hour reset pulse used in 3-wire systems. This revolutionized the industry since occupants no longer had to wait until the next day for clocks to be on time after a power interruption.
National Time Rotary Drive Synchronous (RDS) clocks were the first mechanism to support this new protocol. The RDS clocks have since been replaced with the Spectrum analog clock and the DLX series digital clocks further improving the technology.
In the early 2000’s, radio frequency correctable clock systems became popularized. These systems transmit the correct time wirelessly to nearby clocks. Depending upon the clock type, they may operate on batteries or local building power. Today, they represent the majority of new clock systems specified in educational occupancies. The main benefits claimed by the proponents of these systems are:
There are essentially 3 types of RF Clock System Types described below
This system architecture uses a high-wattage transmitter capable of covering an entire building or campus. Due to the high transmit wattage necessary, an FCC license is required for the site. If a nearby area already has a license, your application may be denied.
Since the distance between the base station and the clocks is large, the clocks do not have enough transmit power to respond back to the base station. Therefore, synchronization is assumed to be successful, and no information such as signal strength or battery level is known without visiting each clock location.
The mesh system may have a base station that serves as the keeper of time or it may be a designated clock within the system. The radio frequency mesh technology can be proprietary or industry standard, such as Bluetooth or Zigbee. The timekeeper of the mesh transmits to nearby clocks, and the signal is repeated to reach further clocks. The signal continues to propagate until all clocks receive the correct time. Synchronization is assumed to be successful, similar to the Site Transmitter example.
This mesh system typically has a base station or a clock acting as a base station. It transmits the signal just like the one-way mesh, but the clocks also transmit back to the base station using the mesh protocol. The base station connects to the internet or a local computer to record the health status of the mesh and the battery levels of the clocks. These systems are more complex in nature, but the benefit is advanced knowledge that time accuracy is maintained and when batteries require replacement.
Commercial Wi-Fi clocks have been available since 2014. These clocks can be powered by either batteries or local building power. They may be analog or digital, although most digital clocks do not run on batteries due to higher power consumption. Additional features such as beepers and class-change countdown timers are also available.
Wi-Fi clocks eliminate the need for a master clock or RF transmitter, allowing clocks to be added to a building as needed.
The investment in the building’s Wi-Fi network has already been justified. The absence of proprietary transmission protocols makes maintenance and troubleshooting widely accessible.
The time is synchronized with an NTP internet time server to ensure precision. Natsco clocks feature cloud-based monitoring to verify both time accuracy and battery levels.
PoE clock systems have been developed to offer a network time-based option in synchronized clock system installations. These systems utilize the building CAT5 or CAT6 network infrastructure.
Power is provided by the IT router equipment through the same cable as the data. A separate cable needs to be installed between the router and each clock. If you need to share a single cable, you will require PoE devices capable of PoE power forwarding, which may increase costs.
The time source is an NTP Time Server either local or on the internet. This will ensure accurate time across all devices.
The cost of installing a PoE system is typically the highest. It requires PoE routers to power all the clocks, and CAT5 or CAT6 cables are more expensive than those used in hardwired clock systems. Adding additional clocks to new locations in the future could be problematic and cost-prohibitive compared to Wi-Fi and RF systems.
Here is a list of typical system layouts and what National Time products could be used. There are variations including Wi-Fi, RF Wireless, and wired systems.
Educational and medical facilities account for a large percentage of clock system installations. Both system styles are used in these facilities, with selection sometimes being a matter of personal preference and sometimes by design. For instance, K-12 schools may choose analog clocks for their elementary and middle schools as an educational tool. Hospitals may choose analog clocks in some locations for the sweep second hand reference and digital clocks where time recording or timing functions are important.
Many perceive the main benefit of analog clocks to be the graphic display of time. The picture of the clock resides in our brains, making it very easy to order our day. With a simple glance, we can see segments of time that are easily understood references. Analog clocks are also aesthetically pleasing and can add to the décor of any room.
Digital clocks, being numerical rather than pictorial, may not be as readily assimilated for most people. Despite this, digital clocks offer quick and accurate readings, which are essential in time-sensitive industries like the medical field.
They also come with additional features such as countdown timers, alarms, and backlighting for low-light environments. However, some digital clocks can emit blue light, which may be detrimental to sleep.
Perhaps of interesting note, it is said that Albert Einstein refused to have digital clocks in his home and study areas as the representation of time as “static” was wholly inconsistent with his thought process that led to the extraordinary findings of time and motion in his “Special Theory of Relativity” published in 1905.
Battery technology continues to improve, and our world now revolves around the portability and convenience batteries provide us in our daily lives. Clock systems, however, are building infrastructure components and portability is not one of their valuable characteristics. Today, Americans throw over 3 billion batteries in landfills every year! This just can’t be a good thing for the environment. Add to this, battery operated clocks are not compatible with “clean” alternative sources of energy available at greatly reduced prices from the electrical grid. If digital clocks are desired, battery power is not an option.
When renovating or replacing clocks on a wired system, the existing wire can be repurposed to power Wi-Fi or RF Wireless clocks. For new clock locations, battery powered clocks could be utilized in those locations to ease installation costs.
Replacing batteries every few years is an expense that should not be ignored when selecting a system.
