A-B and DeviceNet

This is what I experieced yesterday trying to connect to Point I/O:s (1734) via a 1756-DNB/A.

First of all I couldn't get online in RSNetworX for DeveiceNet. The only thing that I had configured was the scanner and the Point I/O, NOT the I/O-modules itself. The reason why I couldn't get online was that I had wrong the version of the EDS-file for the scanner. The software offered me versions 1 to 4, and I had choosen version 4. My scanners version was number 5 according to the labels on both the package and the module itself. So I went to the AB-site and downloded the version 5 of the EDS-file. And yes I could get online after this. BUT there was one problem. The actual version in the scanner was NOT version 5, it was version 3.xx. The software offered me to change it to the correct version, I accepted.

Then I tried to scan the network but it couldn't find all the I/O-modules. After calling the support for the xxxx amount of time the told me it might be a problem with the addressing of the modules. So they made me go online and change all the addresses on those modules that was found. And what happened, of course some new modules appeared. After I finished up there is still two modules missing. Why I don't now. I have also tried to start with a new "project" in RS NetworX without anything configured and get online to scan off the network. The result of that is as follows.

After scanning the network, there is still two I/O-modules missing and here it comes. It can NOT find the scanner itself, but I can scan the network. So there am I now. I'll give a try to lunchtime. If it doesn't work then. There is only two ways to go for me. A-B people has to visit me in a jiffy and fix their god forsaken system or it will be flying A-B products outside my company windows. And I'll buy a DeviceNet scanner for the GE Fanuc 90-30 system. That I know is working at a glance.

:angr:

It can be a little tough.

Without knowing the number of nodes or the lenght of your network.
Try the basics first.

1. Is it wired correctly and are you using device net cable.

2. Is you powersupply sized correctly.

3. Do you have the terminating resistors at each end. 121 ohm?

4. And do you have the baud rate set the same on all the devices, set
based on the length of your network.

5. Also try to configure it one device at a time, start with the
ones that are not communicating.

I ran into the same problem a few weeks ago.

Crawl, Babysteps, walk, then run.

1. The setup is wired correctly according to the manuals.
2. The 24VDC power supply is on 6A. And I don't have any heavy loads.
3. The terminations is done by the resistors delivered with the scanner.
4. The baud rate is 125.
5. It doesn't help att all.

The rack of I/O-modules is divided into three sections in one row. First section contains one Point I/O + one Ana out + two Ana in + 8 Dig In. The second section has only 4 Dig In, the third section contains seven Dig Out. That is what has been powered up as for now. Inside the cabinet there is also two PowerFlex 40 drives that is going to be ran from tne DeviceNet bus.

But I hope every problems will be solved today because I'm having support guy from A-B coming and fix it, hopefully.

Wish him luck :|

I can contribute some nuggets of knowledge to each of your paragraphs.

When you "go online" with RSNetworx, try it with an empty project first. This will allow the software to automatically detect the devices that are on the network and add the proper entries into the project file. You won't have to go through that "I chose V4 but I had V5" sort of thing. If the device is on the network but you don't have the EDS registered, it will come up as unrecognized and you can go get the EDS (if you are connected to the Internet, the software will retrieve the correct EDS for you.)

The node number of the 1756-DNB can be changed using the Node Commissioning Tool, or with the pushbutton on the front of the module. With the DeviceNet power off, that pushbutton sets the data rate. With the DeviceNet power on, the pushbutton sets the Node Number. Press and hold the button until the node you want shows on the display, then release it and the module will reboot.

Almost everyone makes the scanner Node 00 on the network. Do not leave it as Node 63.

New devices that do not have hardware switches to set the Node Number are always Node 63.

Every POINT I/O module that comes out of the box is Node 63.


The first thing to know about POINT I/O: there are three different interfaces.

1734-PDN passes DeviceNet signals right to the POINT backplane and does not take up a node number. POINT modules connected to this device will communicate directly with the master.

1734D blocks have their own node number and also pass DeviceNet signals to the POINT backplane. POINT modules connected to this device will communicate directly with the master.

1734-ADN and 1734-ADNX have their own node number, and scan their POINT backplanes to present a composite assembly of I/O data to the scanner. The POINT modules attached to them do not directly communicate with the master.

Hey, we're cookin' now.

Go over that assembly again, and let's throw in some part numbers.

The rack of I/O-modules is divided into three sections in one row.

Click to expand...

What is between these sections; are there 1734-FPD field power separator modules, or 1734-EP24DC expansion power extenders ?

First section contains one Point I/O + 1 Analog Out + 2 Analog In + 8 Discrete

The second section contains 4 Discrete In.

The third section contains 7 Discrete Out.

Click to expand...

What is that first "Point I/O" module ? Is it a 1734D, 1734-PDN, -ADN, or -ADNX ?

I will have to get out my POINT selection guide to refresh my memory about how many devices are supported per segment on the POINT backplane.

I'm also curious about the exact part numbers of the modules.

Because everything comes out of the box as Node 63, usually you hook up some POINT modules and all you see is Node 63. All the other new POINT nodes have a red light, because they are Node 63 as well and are politely declining to join the network.

To remedy that, you change the first module to the starting node number for your POINT modules. Then you go online with it's parameter list and enable a function called "Sequential Auto-Address".

This function does exactly what you think it does; the modules use a special function of the POINT backplane to number themselves sequentially left-to-right.

I have a 1734D block on my desktop, set for Node 1. When I get POINT modules for which I don't know the node number, I plug them into that and use Sequential Auto-Address to set them to Node 2. I don't even wait for RSLinx to find them ! I can then change them them to whatever node number I want.

Oh, here it is;

12 modules with 1734D or 1734-PDN. No POINT backplane extenders allowed.

63 modules with 1734-ADN or -ADNX. POINT backplane extenders are needed as required for each group of up to 17 modules.

Spiff's system has 22 POINT modules, so it is too big for a 1734-PDN and must use a 1734-ADN(X) (unless it has been incorrectly put together or I misunderstand his description).

The -ADN is a little more complex because it actually acts as a sub-scanner.

You will have two *.DNT files; one for the DeviceNet with the 1756-DNB as the master, and one for the DeviceNet subnet with the 1734-ADN as the master.

Stick with it, Spiff ! I'll be up all night watching election results anyhow.

(and yes, the election isn't over in my state.)

Ken Roach said:

(and yes, the election isn't over in my state.)

Click to expand...

This is becoming all too familiar. Good luck, Washington.

First, thanks for all suggestions.
Yesterday I got professional help from the local Rockwell technician. His conclusion during the first 15 min of his visit was that everything was normal and correct. But then he explainned to me the "thing" that solved everything. Since the Point I/O-module was a 1734-ADN inside the cabinet. He told me that this module is a "router". Since I'm familiar with IP technology this is the best similarity I could find. With theese magic words the world opened up.

As you all have discused/explained here ealier this Point I/O-module is intelligent and has it's own scanner and therefore it's own "subnet". So now everything is clear to me in this matter.

Then when I got theese two "subnets" I had to make connection between them. It wasn't that easy what I can understand because it could only being done only in one way. From the DevScanner to the Point I/O. Not both ways, probably because of a bug in the software or something. I dont't care at the moment.


My conclusion after this experience is that I still prefer ProfiBus, unfortunatly thou. It's easier to set up and get running.

Thx again