Port Type "DLL's Ground"

First noticed this a couple of days ago and can’t find the topic in the help file or in the forum. I’ve not been using this in my DLL schematics and things (mostly) seem ok. But I’m guessing that it’s there for a reason and I’m missing something that will bite me in the backside later.

When is this port needed and what does it do?


As far as I understand, the implicit DLL ground is the ‘normal’ ground. A voltage on the DLL ground input will give you a respective voltage offset from ground.

Thanks, @Jope. I had similar thoughts. However, I was hoping for an authoritative answer ala @Engelhardt.

If it’s as simple as a “reference voltage,” there would be no obvious need for a special DLL ground – we’d just add a reference voltage input and subtract. Or maybe that’s exactly what it is and there only as a convenience and we just tie it to a reference on the parent schematic only when not circuit ground.

Anyway, just want to be sure that there’s not some other, less obvious implication.


Edit: At a minimum, I think that it should be documented in the Help file.

But, in the end, what is the purpose of DLL GND?
From my simulations I can’t see a useful way to have it.

If you create a Ø-Device without input port, you have to add a DLL’s Gnd.

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An error will return if no GND for output port only Ø-Device


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The inputs and outputs of a .DLL go through a converter. If there’s no DLL GND specified, the converters operate ground referenced. If you give a .DLL a GND, then inputs and output are referred to that .DLL GND port. It let’s you run your logic hot decked as one might in an offline converter.


Oh, didn’t think about Ø-Device can be float with DLL’s GND until your explanation.

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Thanks @Engelhardt and @KSKelvin !!