Latest revision as of 14:07, 4 November 2013

Smart String Controller (SSC) Comparison

The purpose of this page is to describe the differences between the various smart string controllers (including Zeus). The comparison includes wire length distances.

Notes:

• PixelNet is carried over 2-wires (a pair) using 5v +PixelNet and -PixelNet. Using a pair of wires (+/-) allows a PixelNet signal to be carried over long distances. While 100ft is reported to be reliable, greater distances can be achieved with shielded cables. Additional devices can be added to extend the distance of PixelNet and DMX... hubs and splitters can be used to regenerate the signal and add additional 100ft runs of cable.
  • DMX is similar to PixelNet. By using 2-wires (a pair) to carry 5v +DMX and -DMX, similar lengths can be achieved. Similarly, repeaters can extend the distance with additional lengths of cable. DMX is NOT used by SSC and Zeus... the comparison is drawn here as background information.

• Lead refers to the distance between the controller and the first node in the string. The wires emerging from the controller carry +12v, Ground, and (Pixel) Data Signal. Data is NOT passed as a pair of wires (as is the case with PixelNet), therefore the Pixel Data signal will not carry for longer distances and will degrade based on several factors:
  • Resistance of the wire
  • Length of the wire
  • Additional resistance introduced with 3-core waterproof connectors (or ANY connector)
  • Reflection over the length of the wire

• Spacing refers to the distance between one node and the next. Spacing can be changed over the course of the string, it need not have consistent spacing. With each node, power is drawn from the 12v wire to light the LED -- and ALSO regenerate the Data signal passed to the next node. Assuming that a node gets an accurate packet of data, with sufficient 12v power remaining it should be able to generate a new packet of data for the next node.

SSC changes over the course of generations -- accomplished through changes in resistors and firmware -- have improved the behavior of the SSC. SSC v1 and SSC v2 can both be modified, see "SSC v1 & v2 Mod" instructions to achieve the optimal behavior found in SSC v3.1 with your older kits.

Null Nodes serve the purpose of Data signal regeneration. Using the behavior of adding new power and creating a new packet of data for the next node, the purpose is satisfied regardless if the light is masked and hidden from view. Inserting a Null Node midway between the SSC and the first visible node can double the distance to that visible node. Null Nodes can be used anywhere in the string to span distances between segments of the string.

DSC (Dumb String Controller) is similar with regards to its PixelNet input, but after the controller all similarity ends. The DSC does not pass Pixel Data signals to the string. Instead, the DSC passes +12v current over the common wire, and (3) grounds to the Red, Green, and Blue LEDs. Current can be passed greater distances than Data signal, so the wire emerging from the controller can be longer -- but the wire resistance will also impact the available current at the strings, with long wires, the lights will be dimmer -- possibly changing the mixture of visible color along with the intensity.

Debugging:

• wire length problems may result in the first node assuming a different color than the rest of the nodes behind it
• insufficient power can cause nodes later in the string to fail to change colors
• large spacing can cause nodes later in the string to fail to change colors
• whites may appear "pink" at the end of the string if power is insufficient (use power inject to address this issue)