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Anyone remember anything about MPX?

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Jonathan Kok:
I've got a client with an older MPX portable dimmer system, using the good old I/F 501 from Leviton to convert from DMX. Worked fine with the constant stream of data from a lighting console, but now we've added a Fleenor button panel to the chain, and they're finding fixtures ghosting on. I suspect the one-shot data from the Fleenor is highlighting a problem that probably existed before...

So, any thoughts? Is MPX termination a thing? How does one wire such a terminator? That's all I could come up with that might help resolve the issue. Short of replacing all their portable dimmers with DMX versions (which would be a waste of money, as they plan on skipping straight to DMX-controlled LED).

EDIT: Also, it's 5:00 on Friday, so if I remember that I posted this, it won't be until Monday...

Scott Hofmann:
If you are using the Fleenor PRE10A, it should not have any effect on the DMX signal flow. The PRE10A sits on the DMX line (does not “interrupt” it) and monitors DMX activity. If there is DMX activity from the main console, it locks the preset buttons out. It is possible to unplug the PRE10A (as in for service), and the main console will still be fully functional. This is because there is no separate DMX in and out; in and out share the same 3 terminals. Are you certain the jumpers on the Fleenor are set correctly?
I believe MPX does not have a facility for or need termination.

John Fruits:
On Monday if you haven't already resolved this, call or text DFD directly.  They do have wonderful tech support.

Jonathan Kok:

--- Quote from: Scott Hofmann on January 06, 2023, 08:41:06 PM ---If you are using the Fleenor PRE10A, it should not have any effect on the DMX signal flow. The PRE10A sits on the DMX line (does not “interrupt” it) and monitors DMX activity. If there is DMX activity from the main console, it locks the preset buttons out. It is possible to unplug the PRE10A (as in for service), and the main console will still be fully functional. This is because there is no separate DMX in and out; in and out share the same 3 terminals. Are you certain the jumpers on the Fleenor are set correctly?
I believe MPX does not have a facility for or need termination.
--- End quote ---

Yep; the chain is Console -> DFD ES2 -> DMX House Light Fixtures (ETC 0-10V modules) -> DMXtoMPX -> MPX Dimmers. The ES2 enables/disables itself properly, so no issues with it. I don't think the ghosting has anything to do with the ES2, just a result of the ES2 pushing the DMX signal out a single time rather than providing a repeating stream. When they had the repeating stream coming from the console, any ghosting would've been immediately overwritten by the console stream.

I suspect the issue is between the DMXtoMPX and the MPX Dimmers. I'll probably just split off the ES2 / House Lights (as that's all the ES2 needs to control) onto their own DMX chain; see if that solves the problem. It'd at least isolate the ES2 in case it's the cause (though I doubt it).

Jonathan Kok:

--- Quote from: Jonathan Kok on January 09, 2023, 11:04:12 AM ---Yep; the chain is Console -> DFD ES2 -> DMX House Light Fixtures (ETC 0-10V modules) -> DMXtoMPX -> MPX Dimmers. The ES2 enables/disables itself properly, so no issues with it. I don't think the ghosting has anything to do with the ES2, just a result of the ES2 pushing the DMX signal out a single time rather than providing a repeating stream. When they had the repeating stream coming from the console, any ghosting would've been immediately overwritten by the console stream.

I suspect the issue is between the DMXtoMPX and the MPX Dimmers. I'll probably just split off the ES2 / House Lights (as that's all the ES2 needs to control) onto their own DMX chain; see if that solves the problem. It'd at least isolate the ES2 in case it's the cause (though I doubt it).

--- End quote ---
Well, I wasn't able to resolve what exactly was causing the ghosting issues, but I was able to work around it. Turns out, the ES2 is capable of sending a continuous stream in the OFF state. By default, it sends 000 to every channel, then ceases to send DMX. But if you record ANY info to ANY channel, it will instead send a continuous stream. So, I added a dummy fixture at the end of the address range, set it to full, and recorded that to the ES2. It'll work until they're able to replace the MPX dimmers with DMX fixtures.

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