If you're running DMX on shielded category cable, what are you doing with the shield?
Grounding it only at the source end?
Grounding it only at the receiving end?
Grounding it at both ends?
Ignoring it, insulating / isolating it at both ends?
I've done a little Googling finding various, inconsistent, answers?
The application is entirely within EMT and four x 24, immediately adjacent, Johnson Systems ICON dimmer racks.
The plan is to reuse the existing Belden 9841 from the booth to the racks as it's in perfect condition and has given zero problems for more than a decade. Connecting Belden's shielded pair is no problem. My only query is how to handle the shield on the very short lengths of category cable within the four immediately adjacent racks.
Why are we using shielded CAT cable in the first place? (You may be wondering.) Because it's what's on hand.
I'm leaning towards using Fleenor / Pathway's pairing / color code and grounding the shields at the source ends ONLY to avoid circulating currents / ground loops on the shields.
This run is dedicated to dimmers only and terminates at the last, fourth, rack. A second run of 9841 routes the board's second output to a 1x4 opto splitter in FOH then, via the 'loop out' on to a second 1x4 opto serving on stage electrics where this second 'loop out' is terminated.
Your thoughts please.
Toodleoo!
Ron Hebbard
Grounding it only at the source end?
Grounding it only at the receiving end?
Grounding it at both ends?
Ignoring it, insulating / isolating it at both ends?
I've done a little Googling finding various, inconsistent, answers?
The application is entirely within EMT and four x 24, immediately adjacent, Johnson Systems ICON dimmer racks.
The plan is to reuse the existing Belden 9841 from the booth to the racks as it's in perfect condition and has given zero problems for more than a decade. Connecting Belden's shielded pair is no problem. My only query is how to handle the shield on the very short lengths of category cable within the four immediately adjacent racks.
Why are we using shielded CAT cable in the first place? (You may be wondering.) Because it's what's on hand.
I'm leaning towards using Fleenor / Pathway's pairing / color code and grounding the shields at the source ends ONLY to avoid circulating currents / ground loops on the shields.
This run is dedicated to dimmers only and terminates at the last, fourth, rack. A second run of 9841 routes the board's second output to a 1x4 opto splitter in FOH then, via the 'loop out' on to a second 1x4 opto serving on stage electrics where this second 'loop out' is terminated.
Your thoughts please.
Toodleoo!
Ron Hebbard