SLC 5/05 to Danfoss VLT over Ethernet

[jedft]

I slowed down the Message Reply Timeout to the max and now the error I get every time the EEM runs is d8 - "Connection was broken" So does that mean the real problem is I am never even connecting to the Danfoss module? If so, why would the write work but not the read?

 

[Ken Roach]

Let's slow things down a little further to examine.

Try disabling the Write message. Does the Read message function when only it is running ?

I usually alternate my Read and Write messages, generally triggering the Read from a repeating timer, then triggering the Write from the /DN bit of the Read.

Post a link to the Danfoss Ethernet Master user manual if you can. If you can post your SLC-500 code, or a snippet of it, that would also be helpful.

If you have a managed Ethernet switch that allows you to do "port mirroring" you could run Ethereal/Wireshark on a port that mirror's the SLC-5/05's traffic, and that would give you a low-level look at the Ethernet protocols that are being exchanged. I also keep a 10/100 Mb/s hub around so that I can install Ethereal as a passive sniffer (with a PCMCIA 10/100 Ethernet interface to my PC that has no protocols bound to it).

 

[Norml]

Well I will tell you alittle that I know about both of them. I had a similar application as you, but mine involved Danfoss' 2800 series book style drives and a SLC 5/05. I installed 80 of these drives originally using a SLC 5/04 and a basic module to talk the "FC" Danfoss protocol to all of the drives on the "FC" network. It was alittle time consuming, but I finally got it figured out and the ladder was quit amazing, but needless to say I got it working and the nice thing about it is they are all on one network with some repeaters in their. So my next project was to add 150 MORE drives. So after looking at all my options Danfoss came to us and said that they have this ethernet BOX that will work with a ethernet network. So after looking into it it came out that a AB SLC5/05 will not talk true ethernet/IP. They wanted me to upgrade to the logix processors that talk true CIP instructions or something like that. Well that was totally out of the question so we scraped all of that and went to a Modbus network with Yaskawa drives. Hope that answers some of your questions.

I've seen the same thing happen with trying to setup a slc 5/05
with Toshiba drives. The Toshiba drive supports a ETH-200 Ethernet/IP module which seems to work with anything but the SLC. This problem actually got out in the field and some enterprising person put a Micrologix in as a middle man to convert to Modbus. I still don't quite understand how it got working.

 

[jedft]

Well, I disabled the write, and the read still does not work. I even deleted the rung with the write.. same thing. Upon further reading it looks like the module, once sent a write command, responds with the status data. If that is the case, I would need an instruction that writes and then reads in one operation.

As usual, time contraints are going to be the decided factor here. The write message is working reliably so I am going to bring a VFD fault contact and VFD speed 4-20 into the PLC and be done with it. That's all the info I was using from the read anyway, really. I suppose the real answer here is don't try to use a SLC with something like this. I wouldn't have except the SLC was spec'd. It just isn't designed for it. Had I been using RSLogix 5000 and a compatible PLC I would have been done 2 days ago.


I really appreciate the help.... off to do some wiring.