Maximum Cable Length: 3m
3 meters between the pixel controller and the first pixel
3 meters between each pixel
As a manufacturer, we air on the side of caution to ensure stable installations and user confidence. This reduces interference and minimize voltage drop, which are crucial for the operation of addressable LED lights.
Longer cable lengths increase the susceptibility to interference due to increased resistance, capacitance, and inductance along the transmission line. To mitigate these issues, proper grounding techniques, shielding, twisted pair cables, and noise filtering components can be employed to ensure reliable SPI communication. If you want to exceed our 3-meter recommendation, we recommend testing the equipment in the intended environment beforehand to ensure satisfactory performance before installation.
The SPI technology is uniform across all manufactures/products, differences in manufacturers recommendations indicates their caution not the products capability.
SPI (Serial Peripheral Interface) data is susceptible to interference in several ways:
- Signal Integrity: SPI relies on precise timing and voltage levels to transmit data accurately. Interference, such as noise or voltage fluctuations, can disrupt these signals, leading to data errors or corruption.
- Crosstalk: In systems where multiple communication lines run close to each other, crosstalk can occur. This is when signals from one line unintentionally affect signals on another line, leading to data errors.
- Electromagnetic Interference (EMI): External electromagnetic fields, such as those generated by nearby power lines, motors, or other electronic devices, can induce unwanted currents in SPI communication lines, causing data errors.
- Ground Loops: Differences in ground potential between connected devices can lead to ground loops, where unwanted currents flow through the ground connection, introducing noise into the SPI communication.
- Reflections and Impedance Mismatch: Reflections caused by impedance mismatches along the transmission line can distort the SPI signal, leading to errors in data transmission.
Cable Length
We strongly recommend a maximum wire length of 3 meters between your pixel controller and the first pixel. This distance limitation is a precaution to minimize any interference being picked up on the unbalanced data line that addressable LEDs require to operate, and to minimize the impact of voltage drop. This recommendation and protocol limitation applies to all brands that output pixel protocols.
As a manufacturer, we air on the side of caution when recommending maximum wire lengths. This helps us ensure that your installation is stable and allows us to have confidence that any user can make the system work without any issues. Our competitor’s recommendations may differ from our own, if you can keep interference at a minimum (no mains power cables running near/past it and using a good quality cable such as 3/4 core 2.5mm TRS in order to minimize the impact of voltage drop) some Pixel installation has been able to achieve distances higher than our recommendation.
If you wish to go beyond our 3-meter maximum wire length recommendation, ENTTEC suggests you test the equipment in the same environment, to make sure you are happy with the results prior to installation.
Cable Thickness
The thicker the cable, the lesser the impact on voltage drop, data degradation and higher the electrical current it can carry.
To determine the cable core diameter your installation requires, determine the power draw of the section of LED strip you will be powering.
This can be achieved by using the per-meter power draw of your pixels as defined in its datasheet and multiplying it by the quantity your project uses.
Add 20% overhead on top of this to factor in power spikes and increased current caused by voltage drop.
Finally, divide this total power draw by the Voltage of your installation to determine its current draw in Amps.
Ensure the cable you specify is capable of carrying the electrical current (Amps) of your installation.
For optimum performance, ENTTEC recommends using cable with stranded copper cores.
2.5mm stranded copper cabling has been found to be the maximum cable diameter that can be soldered to the pads of ENTTEC pixel strip.
It's recommended that a cable voltage drop calculator is used factoring in the cable you have selected when planning your installation to ensure the voltage remains in range.
If you are using a power supply with a higher current capacity (A) than your cable is rated for, fit a fuse to protect your cables from becoming damaged if a short circuit or other fault situation occurs.
Environmental factors should also be taken into account:
- Ensure the cable selected is rated to handle the power draw of your installation.
- Ensure your cable is sufficiently rated for the Installation environment. i.e. If outdoors ensure the cable is UV resistant, or if being buried ensure it is armoured.
Splitting Data
It is possible to Y-Split data entering pixel strip to duplicate the signal on a synchronous onto more than one length of strip to reduce the number of controllers required.
Note that this results the content on each pixel strip being identical.
To reduce the impact of noise generated in the cable or data bounce back. It is recommended to split the data cable as close to the Pixel strip as possible. – As with any pixel installation, data cabling should be kept as short as possible.
Always test your proposed setup ahead of rolling it out on an installation.