adccommunitymod (AutomationDirect) asked a question.
Modbus and GS-RS485-4
Created Date: September 13,2006
Created By: 72hdflh
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Has anyone used the GS-RS485-4? The instruction sheet is very vague. Where do I need to place the termination resistors. Do I need belden 9841 for the whole thing or only to the GS-RS485-4 then cat5 to each drive? http://forum1.automationdirect.com/board/confused.gif
Created Date: September 14,2006
Created by: Tech Guy
The wiring distance to each drive from the GS-RS485-4 needs to be as short a distance as possible. The termination resistor can be placed on the line that feeds the GS-RS485-4.
I recommend Belden 9841 to each drive, but if the distance is short enough you might get by with CAT5E.
Created Date: September 14,2006
Created by: 72hdflh
TechGuy,
An interesting thing I found in the newest GS2 drive book says that the termination resistor is only needed on large runs?? I ran into a problem on an Allen Bradley system a while back, where the resistor had fallen off and it did not work at all without it.
Created Date: September 14,2006
Created by: Tech Guy
It all depends on the system and the amount of noise present. In my office I can usually get by with a few feet of wire (around 3-4 feet) without termination resistors. Sometimes I need them, some times I don't.
I typically use them whether I think it needs them or not just because as components age sometimes the impedence changes.
Created Date: September 15,2006
Created by: 72hdflh
Tech Guy,
I got it working with just CAT5 on my desk. I have the 9841 and resistors on order to do it properly when it gets installed on the floor.Is the GS-RS485-4 a relatively new product? It really does need better documentation. Thank-you for the help. http://forum1.automationdirect.com/board/smile.gif
Created Date: September 13,2006
Created by: 72hdflh
Has anyone used the GS-RS485-4? The instruction sheet is very vague. Where do I need to place the termination resistors. Do I need belden 9841 for the whole thing or only to the GS-RS485-4 then cat5 to each drive?
http://forum1.automationdirect.com/board/confused.gif