Two scanners on one DeviceNet?

I don't recall ever commissioning or editing a DNet network without a direct interface.

That is what I am going to do. I've pee'd away enough time on this and could find that to be the problem - inability to do a pass-through.

The previous times I've done DNet *mods*, I have never connected directly to the net. It must be something funky about the first *config*.

I thank you heartedly for your help and attention - DM, Ken, and George!

RoTaTech said:

That is what I am going to do. I've pee'd away enough time on this and could find that to be the problem - inability to do a pass-through.

I thank you heartedly for your help and attention - DM, Ken, and George!

Click to expand...

No problem...Let us know about the outcome though...

At a previous job, we used an Ethernet to DeviceNet gateway on each network. I believe the part number was 1788-EN2DN

I liked that method much better than the PC card/cable and with them a permanent part of our LAN, we could hit them from our office workstations and update devices, troubleshoot, etc. We didn't use them for actual I/O connections to Ethernet IP controllers, just as easy access to the Devicenet network after finding out how impossibly slow passthrough was for downloading a VFD etc.

I don't believe having two scanners on one DeviceNet, with both scanners having the same devices in their configurations, is supported, or even desirable...

Don't forget that nearly all DeviceNet devices have output data as well as input data, surely there's going to be conflicts.

Sure, you can use the physical DeviceNet with multiple scanners, but the field devices can only be configured in one scanner...

Thanks Daba. I wasn't looking to control them that way, my thought was I could upload the network and then upload the scan table from the 1746 scanner, using the 1769 scanner as a KFD ...

RoTaTech said:

Thanks Daba. I wasn't looking to control them that way, my thought was I could upload the network and then upload the scan table from the 1746 scanner, using the 1769 scanner as a KFD ...

Click to expand...

I don't believe you can use a "scanner" as an alternative to a KFD, I may be wrong though...

But it would be definitely wrong to add network devices to more than one scanner's scanlist... (unless of course they are both sending the same output data)......

Latest update:

On Sunday night at home, I got the idea that maybe two SDNs were conflicting (on backplane, not on same DNet). After I loaded the scan list again through the U2DN, we started to see 78 codes, so I hoped that was the problem. (no network available though - ergo no devices). I came back to site on Monday.

Now I have code 91 on the network. I also tried disconnecting the blue and white out to the field, so nothing is on the network but the 24V, SDN, terminator resistors, and the U2DN. Still I have code 91.

Any more ideas will be appreciated!

DeviceNet Bus-Off Error 91 Causes and Troubleshooting

26046 | Date Created: 08/26/2003 | Last Updated: 12/28/2016
Access Level: Everyone

https://rockwellautomation.custhelp.com/app/answers/detail/a_id/26046/page/1

1747-SDN master and 1769-SDN slave

I have an existing 1747-SDN that is communicating to a third party card (That device controls 12 drives). We want to get rid of the 3rd party eventually so I have set up a Controllogix L36 PLC with a 1769-SDN card. When I look at the documentation about slaving there it seams easy enough.

So I added the existing third party card to the new 1769-SDN card I don't want to control the outputs so I removed the output table from the 1769-SDN.

When I look at the 1747-SDN card it tells me there is a conflict. since there are two devices looking at the card. I guess this is not the way to do this.

Is there a way that the 1747 and 1769 can share the inputs. I really don't want to touch the 1747.

A second issue is that all 1747 SDN I/O is 16 Bit whereas the 1769 controllogix is reading in at 32 bits can this be changed so that it reads the first 16 bits and ignores the balance.

Thanks for any help, I know i can figure out the 16/32 bits but the master slave thing has me stumped.

Ronny, your question is different enough from the original that it would be best to start a new thread.

When you do, please let us know more about that third party device. I'll bet it's a DeviceNet/Modbus sort of interface, but I'd like to know about it.

For the 16 bit / 32 bit mapping, the standard method is to use the COP instruction to move data to and from an INT[x] data array to the DINT[x] I/O array tags.