Configure a 1747 SDN on Rs Logix 500


Thread Starter

Kevin Schiiler

I would like to find an example of configuration of the 1747 SDN in Rslogix500 for my devicenet network. The nodes are all SMP3 starters.
The maximum number of nodes on a network are 12. It is my understanding that the starters send back two words of status and receive one
word for operation. I don't have the devicenet software as of yet but I am not close to the site and therefore can't set it up using the
software anyway. I was hoping to program everything in Rslogix500 and map out all of my nodes in Logix500 and then map out the devicenet
when I arrive on site. My concern is should I use the discrete words or M0 and M1 files. I don't think the quickpanel will be able to
directly access the discrete words and was wondering if anyone has come across examples using both discrete words and the M1 and M0 files.
I have a SLC with a 1747-SDN on my desk right now.

I dont really know what you are asking here but I will try to help you if you can be more specific.
I always use M files, I cant remember why, but I think it had something to do with copying to the O: file, but Im not sure. I am sure you can map to both because if you dont change the setting in RSNetworxs it will automap to the discreet by default. I have seen this mistake made when adding nodes to an existing network. The scanner will have all existing nodes mapped to the M
files, a node will be added and the scanlist automapped, but the default automap is to the discreets so thats where the data ends up.

There really is no setup to it. Just get your data from the M files.

There is a bit that has to be set for the SDN to be enabled that got me once. I think its the I:x/0
bit but I would have to look it up to be sure.

Email me at [email protected] and we'll get this thing working. I also have working ladders using the 1746-SDN module.

Xavier Valls

I have been programming a DeviceNet network with some inverters, a couple of IO modules and a PanelView 550 (total: 24 nodes). I used the RSNetworx Software to configure the network. I used M0-M1 and IO discrete together in the PanelView, it is not so dificult, I can send you the configuration file if you tell me your mail.



Mr. Schiiler,

SMP-3 overload relays are very straightforward to set up on DeviceNet with the 1747-SDN. With your system, you can leave almost every setting at default in their SCANport-to-DeviceNet interfaces.

SMP-3 overload relays with 1203-GK5 or 1203-GU6 DeviceNet interface modules exchange four bytes of input data and four bytes of output data with a
DeviceNet scanner. This maps out in the SLC-500 I/O table with the first
two bytes occupying one 16-bit data Word, and the second two bytes
occupying the next. This is the default setting for the -GK5 and -GU6

The 1747-SDN has 32 words of discrete I/O space, with Word 0 reserved for command and status of the module itself (you have to set Command Word Bit 0 =1 to put the module in RUN mode). The module also supports 150 words each of M1 and M0 "module file" memory for I/O, accessed with COP
instructions from ladder logic. The rest of the M0 and M1 file memory is for explicit message control and scanlist diagnostics.

If you have twelve SMP-3 overloads, that's 24 words of data, an easy fit in the I/O table. If you just number the SMP-3 nodes sequentially on DeviceNet and hit "auto-map" in the 1747-SDN configuration applet in RSNetworx, you'll get:

I:n.0 1747-SDN Status O:n.0 1747-SDN Command
I:n.1 SMP-3 #1 Status O:n.1 SMP-3 #1 Command
I:n.2 SMP-3 #1 Feedback O:n.2 Unused
I:n.3 SMP-3 #2 Status O:n.3 SMP-3 #2 Command
I:n.4 SMP-3 #2 Feedback O:n.4 Unused
I:n.5 SMP-3 #3 Status O:n.5 SMP-3 #3 Command
I:n.6 SMP-3 #3 Feedback O:n.6 Unused
and so on.

Where I noted the second output word is "Unused" above, it's still part of the I/O connection over DeviceNet, it's just that the SMP-3 doesn't do anything with the data in that word.

If you are using the special 2100-GK61 SCANport-to-DeviceNet interface module, it has four input points which, for the sake of simplicity, are mapped as two more bytes at the beginning of the I/O connection. This makes the input connection six bytes and the output connection four bytes (lopsided, something I don't like). Six times twelve.... now if you just Automap, the data is too big for the I/O table itself, and you'll have to get a quick education on "advanced mapping" of data from the I/O connection to the SLC data table.

One mistake I often see with the 1203-GU6 interface is that it's default action upon the DeviceNet going idle (i.e. the SLC is in program mode) is to fault the SMP-3. It's easy to configure the Idle Fault Action parameter of the 1203-GU6 to simply de-energize the overload instead of faulting the SMP-3. Resetting the SMP-3 programmatically is also very easy, that's Command Bit 02.

A neat feature of the SMP-3 is that the parameter whose value is represented in the Feedback word is by default the Average Current. By
manipulating Command bits 13, 14, and 15 you can get that value to represent the other three monitoring parameters. Status input bits 13, 14,
and 15 handshake back the designator bits. Users often compare the "Full Load Current Setting" value (which reflects the DIP switch settings on the front of the SMP-3) to the Average Current reading in order to calculate a
percentage of max load. That can also tell you if somebody changes the current setting while you're not looking !.

I teach the local class on A-B motor control networking in Seattle. If you have any more questions please drop me a line.


Ken Roach
Tech Specialist
Rockwell Automation / Seattle
[email protected]


Trevor Ousey

Most of the time its personal preference to use I/O or M0/M1 to map the devices. My line of thinking is map the command/status word to discrete, and map the other words to M0/M1 files. Note that you can map various bytes of a device to discrete and M files. Avoid using automap with RSNetworks.

Possibly there could be some examples on the Rockwell website knowledgebase. What is quickpanel? If it is like Panelview, maybe it would be better to group all the data in one contiguous file, and use copy and move commands to orginise your data.