School Bell, Campus Clock Tower Clock, Outdoor Tower Clock, Kexin Intelligent Synchronization Movement

Kexin Architectural Tower Clock Product Structure:                                                              Clock systems are divided into indoor and outdoor sections., the interior is further divided into master clock systems and PC monitoring sections, etc.

The outdoor section is the sub-dial, which can be further divided into the movement, hands, scales, and lighting system, etc.

● Principle Introduction

The master clock has its own clock circuit, generating second signals, with an accuracy of0.04 seconds per day, while the CPU continuously receives time signals from the GPS signal receiver, correcting its own time signals to ensure accuracy.

The master clock continuously sends time signals to the slave clocks, and the slave clocks accumulate time.At 15 seconds, the output drive signal activates the motor, completing the timing operation.

The subordinate clock transmits its status back to the master clock and accepts its monitoring. At the same time, the subordinate clock's timekeeping is also monitored by a feedback switch, ensuring the entire subordinate clock forms a closed-loop system. The master clock and subordinate clock together constitute a larger closed-loop system, thereby guaranteeing the entire system's accuracy.

● Master Clock Section:

a）Control System: The master clock is the control center of the system, issuing various control commands and signals from the master clock to manage the entire system's operation.

The master clock features a clock system with timing accuracy equivalent to the system's timing accuracy. When the system is powered, the system's timing accuracy is maintained.0.04 seconds/day, the internal timer can maintain operation for over 10 years during power failure.

The master clock controls the running time of the slave clocks. During system installation, the time of the slave clocks needs to be adjusted on the master clock.The CPU determines whether the subordinate clocks are running normally, speeding up forward, or speeding up backward based on the time of the subordinate and master clocks. If the system loses power at any time, the master clock can remember the time of each subordinate clock. When the system powers on again, the master clock continues to run based on the remembered subordinate clock times. The main control cabinet requires 9 wires to control the running of each subordinate clock, with 6 wires being motor drive lines and 3 being core feedback lines.

b）Cabinet: The master clock is housed in a tower clock-specific outdoor waterproof cabinet, height of1200mm, equipped with power supply and door lock, front, back, and side panels are all removable, surface treated with washing, phosphatizing, and hot-dip galvanizing before powder coating, outer surface meets national standard level 2, inner surface meets national standard level 4. Powder coatingThe plastic surface is matte, with even coloration. The flatness does not exceed within a square meter area.1mm, free of wrinkles, cracks, burrs, weld marks, etc. at the surface corners, the gap between the door and frame is less than 1.5mm, all sides have waterproof designs, the door opens smoothly with no sticking or jamming.

●Sub-chime section:

1、Mechanical actuating section：

a、Casing Appearance: The core shaft is electroplated, and the casing is spray-painted. The core is fully enclosed, oil-free, corrosion-resistant, moisture-proof, shockproof, low noise, low wear, and has a long service life.

b、Mechanical Construction: The tower clocks produced by our company are driven by a constant current chopper method.

The motor shaft and worm shaft are rigidly connected, making it easy to ensure the concentricity of the two shafts.

2) The primary gear uses a worm and spoke structure, quickly reducing the transmission ratio, making the design simpler and more compact. This transforms the originally complex core variable speed structure into a very simple miniature reducer, ensuring quality more easily.

3) Revolutionize traditional connection methods for a compact, rational design that ensures core operation reliability.

4) This core is particularly well-suited for constant current chopper circuit design, ideal for constant current chopper drive methods.

2、Electrical Control Section:

a、Time Signal: Strike ClockThe CPU (AT89C51) receives the standard time signal from the master clock once per second, then compares it with its own elapsed time to determine its operation (normal operation, catch up, reverse, wait).

b、Movement Monitoring: Add a feedback switch on the movement shaft, introduce another closed-loop control, and continuously feedback the position of the clock hand to the sub-clockCPU, the sub-clock CPU compares the feedback signal from the timing switch (actual timing position) with the timing based on its internal memory (theoretical timing position), adjusting the position of the clock hand in real-time to ensure accurate timing.

c、Driver Circuit: Utilizes a constant current chopper drive method, incorporates closed-loop control to ensure constant current, and guarantees the motor operates smoothly without losing steps, with low power consumption (only 1/3 of constant voltage drive power)(1/6), Timekeeping accuracy. Principle as follows:

SubclockThe CPU sends control signals to the drive circuit at a frequency of 15kHz. It latches the drive signal from the CPU on the rising edge of the signal, activates the drive when the drive signal is low, causing the stepper motor to move one step. Meanwhile, the feedback resistor in the circuit continuously monitors the current. Once it reaches a certain level, the feedback signal activates the feedback loop, cutting off the drive circuit, and the current drops. When the current falls to a certain level, the feedback loop is closed, and the drive loop is reactivated, repeating this cycle to ensure a constant current throughout the drive circuit.

3、Lighting section

a、Lighting Area: 24 hoursLighting can be set at any time within 24 hours; the factory setting is from 5 PM to 6 AM the following morning.

b、Luminescent Body: During external illumination, the luminescent body utilizes a diameter of5 LED's in red, green, and yellow, with typical brightness of 600mcd; wavelengths are 640nm red/525nm green, lifespan over 100,000 hours; for internal lighting, uses Philips cool light tubes for soft, even illumination, suitable for years of continuous use.

c、Lighting Power Supply: For24V AC power supply.