Connecting to AB SLC5/03 plc via DH 485


Thread Starter


<P>I am connecting my 1784-ktx card directly to slc5/03 using DH485.</P>

<P>Do I put a 150 ohm resistor at both ends ? & betwean which terminals
<BR>Is the RJ 45 conection on the SLC numbered from the top down ?
<BR>My connection is as follows:</P>

6 pin phoenix on 1784-ktx slc5/03 RJ 45 8 pin
1 chassis gnd ( also screen) 7
2 shield 6

4 DH485 A 1
5 DH 485 B 2
<BR>What happens if you connect the earth ground & Signal ground & the shield/drain all

<P>Answers to any or all questions will be appreciated.</P>

<P>I have looked at the document on the rockwell knowledge base but it does not show the connection of the resistors. (Article G16833 at <a href=""></a> )


Theo Baarslag

I checked the documentation for that port, and apparently the RJ-connector does not have the capability to drive the DH-485 network directly; you will need an interface converter for that. This is the text for that port:
{DH485 - used to interface the module with the DH-485 network. This port is not isolated and cannot directly drive a multi–node DH-485 network. You must use a 1747-AIC link coupler to connect this port to a DH-485 network that includes multiple SLC 500 processors.}

There is however a cable that can connect one device to that port:
{The 1747-C13 cable can also connect the module’s DH485 port directly to a single SLC processor. It connects between the DH485 port on the module and the DH485 port on the SLC 500 processor.}

The pinout for this connector I could not find either, it is really only meant to connect AB standard drop cables I guess. Other cables I think are encouraged to use the 9-pin connectors, which can be set to DH485 by means of the jumpers on the circuit board. The pinouts for those are easy to find in the documentation on "": .

Theo Baarslag
for the IAMS Company, makers of superior quality dog-and catfood
IAMS Europe bv
Coevorden, The Netherlands