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Old May 25th, 2008   #10
svanciel
Junior Member
 
Join Date: Feb 2008
Location: Orlando, FL
Posts: 16
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Hello Milton,

I'm going to have to go back and re-read the Wybron equipment manuals (yes, I actually read them before) to hunt for the loop back wiring scheme you mentioned. This does not sound at all familiar from prior reading, discussions with Wybron reps, nor a good deal of prior scroller experience.
What I do recall is a through discussion of the "head-feet" calculations that are required in order to manage the line loss issues for power.

I understand how a loop back could be helpful to the power side of the equation, but don't recall ever, or anywhere, seeing such a recommendation for a data line, DMX or otherwise. Should I go back and re-read Recommended Practice for DMX512 as well?

The discussion basically started when I was trying to track down the cause of one set of three scrollers constantly being reported in InfoTrace as being Dropped, yet they continued to function correctly in cues. What I discovered was a NEMA wet-location rated electrical box that was full of water. The box contained a 4-pin Neutrix output jack with an ETC printed circuit board soldered to the terminals with a Euro-connector to mate up with the cable (in conduit) from the power supply. There was a lot of corrosion at this junction. Replacing the whole jack resolved the issue. My conclusion was that DMX could blast through alright but RDM suffered. Scott B essentially confirmed this.

We have other RDM error message issues. One of the suggestions from Wybron reps was to install the terminators on the scroller runs. The previous "dumb" scrollers that were in place for 8 years had worked quite well without them. We have fourteen separate runs to groups of three and four scrollers. The distances are within the head-feet requirements but it would be a major project to attempt rewiring each of these runs with a second cable to the dimmer room where the power supplies are housed. The terminators seem to have helped cut down on spurious error messages. My next project is to check and rework all of the output junctions with a more water tight junction to see if that eliminates more of the reported errors such as device dropped, initialization failure, and/or RFID read errors.

One nice feature of the Aquaram IT scrollers is a report back of the voltage and motor current values. As I recall, these readings indicate that power line loss is not a major issue but it is something I will double check.

Hope you have a nice Memorial Day weekend.
SteveV
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