Allen Bradley SNMP messages

[Jonkers]

Hello all.

I have searched and it seems possible but I am still not sure how to go about this.

We have a chassis that has an en2t card and I am hoping to be able to get information from different devices using snmp. Mainly some Cisco switch temperatures and voltages from a Helios dc distribution panel.

There is an older post from some years back here and also says it’s possible but I can not see any good examples of how to achieve it.

Thanks

[gclshortt]

http://www.plctalk.net/qanda/showthread.php?t=108334

The above thread may help you out.
Regards,

[Jonkers]

Thanks.

Doesn’t tell me to much but I never thought of the firmware so will check that.

[Ken Roach]

There are zillions of SNMP middleware devices and software products specifically because it's so fiddly and complex. While you can *probably* implement an SNMP poller or even a trap receiver with Logix open sockets, I'd want to hear a really good justification for spending the time.

"For the same reason that I have a Raspberry Pi emulating the 1988 Macintosh OS" is a good one.

Let's start with: are you going to poll those switches and power supplies, or set them up to announce SNMP traps ? Do they support SNMP v1, v2, or (you almost certainly can't do encryption on the Logix) v3 ?

[Jonkers]

It was just something I thought of while on break and started looking at to see if it was possible.

As I said there is some information around that says it is possible.

I am back on site today so hopefully will get to look into it some more over the next few days. Main reason was we have all this stuff already and wouldn’t need to buy anything new and it is more of a nice to have rather than plant critical.

But if it is crazy hard then I guess we will have to work out benefits vs costs.

But it would be v2. I was just going to poll the devices every minute or so.

[Ken Roach]

It would be fun to write an SNMP poller in Logix open sockets.

But if it were me, I would use some sort of middleware.

It took me the usual trial-and-error to get the arguments, addresses, and Javascript syntax right, but I was able to get a Raspberry Pi running Node-Red to poll the uptime from the printer down the hallway and write it into my testbench ControlLogix. That's the sort of task I like to assign to a little embedded computer instead of my mission-critical controller.

[Jonkers]

So after seeing your post and heading back to site this week. I ended up going down the node-red route and got it working on the test bench.

Used net-snmp calls from a function block as everything was v3 and no v3 nodes. Then used the cip Ethernet ip node to pass it on to the plc.

Just need to come up with a solution now to put it into the production environment.