From practice

Let´s assume there is an existing DMX network on stage as shown below.

From the lighting console all the LED fixtures/dimmer packs are linked with DMX cables. DMX addresses from 1 to 350 are in use.

Merge means: combine two DMX address ranges in ONE DMX universe (512 channels).

Let´s put the LFX Master DMX in the DMX chain behind the lighting console.

Suppose the DMX start address of your LIGHTNG FX BUILDER set-up is 101, and uses 34 DMX channels (in this example two Skypanels in mode 16, “GEL are in use), last DMX address would be 134.

OOOPPPS. Because the LFX Master DMX is behind the lighting console it would overwrite channels 101 to 134! The both DMX ranges must not overlap!

Originally controlled by the lighting console lamps in this address range would do something completely different!

Solution

Find out which DMX channels are used in the existing DMX universe.

Based on our example shown on top set the DMX start address of the LIGHTING FX Builder set-up to the last used DMX address of the stage set-up + 1 channel.

DMX address 350 (last DMX address used in original DMX network)  + 1 (next available address) = 351!

This is the smallest DMX start address for your set-up.

HINT: it does not play a role in which order the additional DMX gear is placed.

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From the technical view

Merging only ever operates with data from two controllers; if a third stream is detected the gear will ignore it.

The LTP mode is used by the LFX Master DMX

LTP: The LTP (Latest Takes Precedence/Priority) will resend input A or B to the output depending on the input that had the latest level change of +/- 1 on any channel. For example with two lighting boards connected (input A and B), the last lighting board that made any change would take precedence and would control the output. If the 2nd lighting board made any change then that lighting board would take control.

HTP: The HTP mode will merge two universes into one universe using HTP (Highest Takes Precedence/Priority) processing of the level of each channel. In this mode two DMX sources can control the same devices. This mode is useful for controlling the same DMX 512 equipment with two DMX 512 generating devices in one universe.

APPEND: The Append mode will split the DMX channels into two parts (the size is user programmable) so the 1st DMX source (lighting board or console e.g.) of 128 ch’s will be sent normally and the 2nd DMX source will start at channel 129 and up. So both are sent on the same universe but not directly combined or would control the same devices. This mode is useful for controlling different DMX 512 equipment or devices with two DMX 512 generating devices in one universe.

BACKUP: The Backup mode will send input A continuously, ignoring input B providing input A is a valid DMX 512 signal. If input A’s signal fails input B will be switched to automatically.

LoTP: (Lowest Takes Precedence/Priority) responds the same way as the HTP mode described above but instead of the highest level sent on a respective channel the lowest level on A or B of the two sources is sent.