IO config.

Gretings to all!
I know you can help me with this issue, I have three 5/04's and one micro 1200 on dh485. 5/04 node 3, 5/04 node4, 5/04 node5, 1200 is unplugged from aic and last on the line. Have additional aic for laptop, plugged in laptop and 1200 and got all x'ed-out on linx.removed 1200, reset nodes on all 5/04 w/laptop to channel 0, gave up trying to connect to node 3 lost comm.rs232 led not on. A link to good ab literature would be great also. attached settings,Thanks friends!

Do you terminating resistors?

no i did not use any , should i for dh485?

Yes. You need the correct cable and terminating resistors.
Rockwell recommends Belden #3106A or #9842.

Termination at each end node of the daisy chain network needs to be 120ohm. Terminal #6 on the Net-Aic module provides this termination resistor for you. You must simply jumper pin 5 to pin 6 at the end nodes only.

Get publication 1761-UM004B-EN-P.

Recommended but not needed

I recently just set up a similar system. I didnt use recommended cables nor terminating resistors nor did I jump them....at first. Set up the communication and everything worked fine. Came back a few days later to finish project and 2 out of 3 nodes failed. What? So I used jumper to use terminating resistor thinking that was the problem. This did not fix the problem.

What did fix the problem was changing the node designation in the PLC's. Changing from node 3 and 4 to node 13 and 14 fixed the problem. I cannot explain why. I really didnt care as long is was working and I could get it to the customer.

You might change the node number of the PLC's and see what happens.

gscure said:

I recently just set up a similar system. I didnt use recommended cables nor terminating resistors nor did I jump them....at first. Set up the communication and everything worked fine. Came back a few days later to finish project and 2 out of 3 nodes failed. What? So I used jumper to use terminating resistor thinking that was the problem. This did not fix the problem.

What did fix the problem was changing the node designation in the PLC's. Changing from node 3 and 4 to node 13 and 14 fixed the problem. I cannot explain why. I really didnt care as long is was working and I could get it to the customer.

You might change the node number of the PLC's and see what happens.

Click to expand...

The node numbering should only matter if you have one or more of them set with a Max Node number that is below the node number of a device it needs to talk to.

It might be that changing the node numbers eliminated a gap in the addressing, which would improve performance, and may have been the difference in your system with questionable cable?

Node numbering on a DH485 network needs to be orderly and consecutive for optimum throughput. You lose a little bit of speed simply by skipping node numbers in the token passing scheme. If you have five nodes, number them 1 through 5 or 7 through 11, but not 1,5,13,15, and 18. I don't recommend setting the max node number value less than 31 unless you must do it to acheive the required performance.

As Paul has already correctly pointed out, proper Cable and Termination is imperative for proper Communications. Allen Bradley would not supply the Termination Resistors with their Communications Cards if they were not necessary.

I have fixed problems on numerous Networks by simply re-terminating the sloppy connections properly, and replacing missing or incorrect Termination Resistors with the proper ones.

Read the instructions, use the correct Cable, and correct Termination Resistors in the correct locations. Usually at each end of Main Network Trunk. You will save yourself a lot of headaches in the future.

If you wing it, it will probably come back and bite you in the posterior.

Stu....

thank you for the advice. I followed the manual's instructions and jumped the terminals and the sheild as specified.My nodes are 3,4,5 max nodes 10, today I was able to see all 5/04's, then chose to daisy chain in the micro 1200 it defaults to 2 and set the comm 0 led on, connected to aic module with proper cable that supplies 24vdc to mod. lost all slc 5/04's on rslinx,I spent 6 hours trying to comm. ready to drop 1200 and replace w/5/04.

Get publication 1761-UM004B-EN-P.


http://literature.rockwellautomation.com/idc/groups/literature/documents/um/1761-um004_-en-p.pdf

In the Manual see in blue above supplied by Okie

On page 5 where is the source of your power supply is it DC Source cable or is it External. ?
you say it goes wrong once you connect the ML1200

What cable are you using from AIC to ML1200
Which serial plugs are you using round or the 9 pin D shell.?

Page 13 do you have a chassis ground connected

Page 15 how many 485 plugs have terminals 5 linked to 6
should only be the very end of 485 cable runs, Total of 2 only. ?

What are the indicator lights showing before and after connecting. ?

How many AIC units do you have. ?

Which DComm light on ML1200 is lit. ?
I don't have one so I think that is how its labelled

I should be learning and not speaking, but I actually have not heard of terminating resistors for a dh 485 network. I have surly had slow comms with it, but with advice I received here I put the nodes from 1 to how many + 1 all runs well.

I'm not sure exactly sure what the "passthru ID link "is for, but you might try setting those all the same ( default is 2 for the SLC's). Maybe the AB guys will help explain that.

Why did you set them different?

I am using cable 1761-cbl-am00 to supply 24vdc tru cable,round connectors,I have 5 aic modules, all units grounded. When I toggle the comm it will lose power to the module , so it must be the comm 0 becouse it powers the module thru the cable. I know it must be a simple node configuration so I will try to just change the nodes and leave the ml1200 default to 2 and count up from there and reset the max nodes to 31.I hear this little voice in my head telling me I should of gone with eni ethernet modules! I will trudge through this today,and one day I will maybe be able to give back,thanks all!

First, take a large step back and be certain you aren't connecting the DH+ network (Channel 1, the twinaxial blue cable) on the SLC-5/04's to the DH485 connector on the 1761-NET-AIC. You probably have a 1761-NET-AIC for every SLC, connected to the Channel 0 serial port, but I want to be thorough.

Okay, now that the obvious is out of the way:

Remember that all of the MicroLogix family controllers use the DF1 Full Duplex protocol by default.

If you plug any controller whose serial port is using DF1 Full Duplex into a 1761-NET-AIC that is connected to a DH485 network, it won't function correctly. I believe that it will interrupt the rest of the traffic on the network, but I can't be sure because I usually don't break things intentionally. Usually.

You mentioned that the MicroLogix 1200 "defaults to 2 and set the comm 0 led on".

Exactly what window and field are you looking at when you say that the MicroLogix 1200 "defaults to 2", and what COMM LED are you looking at ?

The MicroLogix has a Channel 0 activity LED, and it also has a "DCOMM" LED that indicates that the controller has been set to the Default Communication settings of DF1 Full Duplex, CRC, 19200 8/N/1 settings by pressing the hidden DCOMM button. That light has to be OFF if you are going to run DH485 protocol.

I'm going to guess that the setting you mention as "default to 2" is the Token Hold setting. Leave that alone; it's a performance tuning setting.

The MicroLogix 1200's DH485 Node Address defaults to 1. This is the value you need to set for "6" so that it is unique from the SLC's already on the network.

What exact driver are you using to connect your PC to the network, and how it it configured ?

Ken,
your correct,it is a default to one, for that reason I chose to start the nodes for the 5/04's at 3 because I did not want to change the settings on this one. I am using the proper cable by the way. I did leave the cat 5 blue cable in the control cabinets just in case I want to try something in the future. I removed the old modicom systems that they never fully got networked.I also have toggled the comm so it would comm. w/ rs232, comm 0 LED on, dc comm OFF.
I have 5 net-aic modules one available for the pc I am using the pic driver to establish comm to dh485, when i do I only see the 5/04's and they are toggling between communicating and losing communication, i go online and immediately have to "retry" communicating.I see nodes 3,4and 5, yet dont see the ml1200. Thank you for you time by the way,I will pass-it-on!