Control Techniques Commander SK VFDs with LON Card

[ctrlguy]

As part of a large job, I need to integrate 14 domestic water pressure booster pumps with Emerson / Control Techniques (how many business names do those people need??) Commander SK VFDs into an LNS network. The network is complete and I have successfully put 3 of the drives on the network. If I connect any of the other drives, the network or a large part of it goes down. The problem occurs whether a drive is running or not, so I don't believe this is an EMI problem. The manufacturer's support people tried to be helpful, but are clueless about Lonworks and, of course, they haven't heard of the problem before. Does anyone have any experience with Lonworks cards on these drives? By the way, they don't even have a service pin on the damn things and two of them came through with no Neuron ID sticker. I can't say I'm impressed. The Danfoss drives with LON cards on the same job have been no problem at all.

[crab master]

Drives running or not doesn't count necessarily. Kill power to the drives so they aren't powered and see if you have issues. I had one setup where with my PC hooked up to the network I would have a lot of problems, found my PCMCIA lon card didn't like the nearby VFD, used a different usb to lon interface and all worked fine. http://hvac-talk.com/vbb/archive/ind.../t-182661.html

What type of wire do you have running between the drives? Is all your LON wire LON compliant? Do you have shielded wire and is it terminated properly? Chokes? Network Topology? Terminator(s)?

Agree with the sticker/service pin, I do think I recall working on a drive where you could find the NID via the keypad.

[ctrlguy]

Thanks for the reply.

The wire is 22-2 LON wire (non-shielded). The network segment is double terminated daisy-chain with a Loytec FT-10/FT-10 router. I have 160 devices communicating fine on this network. It's just these drives I'm having a problem with. I tried a toroid choke near one set of drives - it didn't help.

I've had the same issue with the PC card interface being taken down by a VFD but I'm using a USB on site and a SmartServer as RNI off site.

[crab master]

160 with only one router?

[ctrlguy]

160 with only one router?

I know better than that. I was referring to the segment. There are 3 routers.

[crab master]

Wasn't spelled out. Also you only say an FT-10/FT-10 router, so that's only 1.

Hmmm - segment? You should only have 64 devices on a segment and 128 max on a channel. Ie segment with 64 to router/repeater then another 64 then up to IP/other backbone/multiport router. I do see you say 3 routers, how many devices on each router?
http://www.engenuity.com/images/Flas...Flash_850.html - if you go to the pdf see pg 33.

I've had problems on a few drives that I changed my wire type to a shielded LON cable and it fixed the problem. That one bit me bad enough after that I started trying to make it policy to run shielded wire to/from and in-between drives. It wasn't always done, so we have plenty without shielded, but if I catch it or the guys do before the pull we make sure we pull shielded.