¶ Genlock Guideline and Recommendations
It is recommended to separate the Genlock sync generator and other high-power devices (such as media servers) for power supply. When the on-site power supply network is optimal, it can share the same power line with the LED controller.
For complex sites, one or more separate LED controllers (such as MX40 Pro or NovaPro UHD Jr) are required to be powered separately from other high-power devices (such as LED screens, lights, and stereos). It is not recommended to use the same industrial power supply box for LED controllers and other high-power devices (this includes LED controllers and other devices sharing the same power supply box but using different power supply ports).
When the stability of the on-site power supply is not guaranteed, it is recommended to add an isolation transformer (model: 1S-1000W/2000W) or UPS (recommended Huawei UPS2000-A-3KTTS and other major brands) before the Genlock sync generator and LED controllers. It is imperative that the capacity of the isolated power supply must meet the requirements of the sync generator and LED controller (MX40 Pro).
Double-shielded cables should be used for Genlock connection. Recommended brands for 12G SDI cables:
¶ Cause of the Issue
LED controllers with Genlock function such as NovaStar MX40 Pro or UHD Jr are commonly used for LED projects such as virtual recording and broadcasting that require Genlock sync signal. The problem of the Genlock sync signal not being locked by the LED controller can be categorized into the following two types:
¶ The Genlock signal source (sync generator) is affected by the noise interference in the power line, resulting in instability of the Genlock signal source.
When the sync generator is placed in the event controller and shares the power line with high-power devices such as media servers and switchers, or when it is placed in the back end of the computer room and shares the same power line with high-power devices such as LED screens, lights, and stereos, the Genlock output signal of the sync generator is prone to instability. This is manifested as the Genlock sync signal of the LED controller at the receiving end being intermittent and unstable and the screen is flickering.
If multiple sync generators need to be cascaded at the site (i.e., the previous generator serves as the main sync source, and the subsequent generator takes the main source as a reference and divides the source into multiple sync sources), when there are high-power devices such as media servers and switchers present in the operating environment of the previous sync generator, the Genlock output signal of the generator is prone to instability, and the subsequent generator may result in synchronization failure as the reference source is unstable.
After turning off or removing all the devices such as media servers, switchers, LED screens, lights, and stereos in the power line, or adding a UPS or isolation transformer before the Genlock sync generator, the Genlock output signal will go back to normal.
Notes:
- AC: Alternating current.
- I1: The current supplied by the power box to the media servers, LED screens, and stereos.
- I2: The current supplied by the power box to the Genlock sync generator.
¶ When the LED controller is interfered by the power line, the interference noise spreads along the cable to the entire system and couples to the Genlock, causing unstable Genlock source and signal loss to the LED controller.
When multiple LED controllers are interfered at the same time, the interference noise spreads along the Genlock cable between devices and affects each other, causing LED controllers to randomly experience unstable Genlock source and signal loss.
When there are high-power devices such as LED screens, lights, and stereos in the same power line as the LED controller and the electricity usage accumulates to a certain threshold, the Genlock sync signal of the LED controller will become unstable and experience frequent signal loss.
When multiple LED controllers need to be divided into several groups to load LED screens in different areas, each group of LED controllers is independently powered and uses a separate power box. After looping the sync signal through all LED controllers via Genlock Loop, when there are other high-power devices such as LED screens, lights, and stereos in the power line of one or more groups of LED controllers, the Genlock sync signal of random LED controller will become unstable and experience frequent signal loss.
After turning off or removing all the devices such as LED screens, lights, and stereos in the power line, or adding a UPS or isolation transformer before the LED controller, the Genlock output signal will go back to normal.
¶ Conclusion
After investigating and exploring the relevant issues of multiple scenarios using MX40 Pro, and conducting interference experiments on LED controllers and Genlock sync generators of different brands and models in the laboratory environment, it was found that the interference noise generated in the on-site power supply was too strong and coupled to the Genlock, causing the problem to occur.
This document provided recommendations for the on-site use of Genlock to guide users on how to avoid such problems.
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