Two DMX Control Systems on a Single Universe

Question

Hi All: 
 We are a small theater in a retirement community. We're currently using a ColorSource 40 console for controlling our stage lighting. We do plays, music groups, and the like. We have a single DMX universe with about 60 fixtures in total. 
 We recently added a couple of SHEHDS moving fixtures to our universe. While we can (sorta) make them work with the CS40, I was wondering about controlling them from a laptop through a USB interface (like the ENTTEC series). My question is can I use a PC/ENTTEC *and* the CS40 console simultaneously? 
 One of the ENTTEC interfaces (DMX USB Pro) has DMX In and DMX Out ports, so I could physically daisy-chain the interface into the network along with the CS40. But is this a good idea? Would this damage the console or light fixtures? 
 Thanks in Advance! 
 - Mike

Richard · Answer

Using two DMX controllers for the same "wire" requires a DMX Merger of some kind. 
 
 These are usually a box that has two (or more) DMX Input ports and one DMX output, along with some controls to configure how the merging should be done. Common merging schemes include "Use the highest level for each slot from each of the input ports" and "these specific DMX slots are always controlled by the input from Port B" or "fade between these inputs using this slider". I don't know of any software that can use the Enttec Pro as an input to a merger as well as an output at the same time. 
 However, I think there's a much simpler solution to your issue: I'd recommend building (or buying) a "#lighthack" to give you physical Pan & Tilt encoders, connected by USB. These are almost certainly the only thing you're missing for your new lights. 
 ETC lighthack kit with all the necessary parts: https://shop.etcconnect.co.uk/lighthack-box-1-kit/ 
 Github page with all the info needed to build one yourself: https://github.com/ETCLabs/lighthack