Noob Questions

[Anonymous]

Good Afternoon all,

I have 2 questions for you guys here: First, How do I connect a cable shield to a ground terminal? Second, I have rung references in my BUS set-up to show (sheet#, Line reference), ie. line ref =0425 for line 25 on sheet 04. I am wondering how, when I do references within the drawing to show that, because now it shows just the line reference?

Thanks in advance,

Jacob Anderson

[TRLitsey · Accepted solution]

Hi there,

Welcome to the board.  I tend to use the shield wire symbol, erase or hide the SHLD and wire to the bottom of the dashed lines.  As for the wire numbers, right click on the Active Project in the Project Manager > Options > Wire Numbers tab and use  %S-%N  or just %S%N.

Good luck

[TRLitsey · Accepted solution]

I should have said that once you make the change to the Project Settings you then need to Apply the Project Settings to the drawing ...

[jseefdrumr]

In addition to TRLitsey's replies, I've attached a screenshot of a drawing I did yesterday that has a shielded cable on it. It's on the upper right part of the image. It depicts a shielded cable arriving from a field device, with a fan-out for all the wires, along with the shield's termination point on the drive. In this case, a terminal was provided expressly for the purpose of receiving the shield from a shielded cable. This is a feature common to most drives and I/O modules that are designed to accept analog signals, or other signals that are sensitive to noise.

Note that further down that same drawing I have a note 'DO NOT CONNECT SHIELD TO SSI'  ...you'll rarely encounter instances like this. Typically, a shielded cable needs to be terminated on either a terminal provided for the purpose on a drive or I/O module, OR twisted up and terminated on the nearest available ground point block or terminal. On the other end, at the device, the shield is tied in to the metal body of the connector, completing the ground.

Hope this helps,

[Icemanau]

Grounding the shield depends on the situation...

A lot of the protection relays I use have in their instruction to NOT ground both ends of the shield in the comm's cable. If both ends are grounded it apparently sets up circulating earth currents between devices which then cause problems with the communication link. Just to note that a lot of the time, these relays are on separate power systems and/or in different buildings.

Shields going out to sensors generally have the shield terminated at both ends but again, follow the manufacturers recommendation.

Regards Brad