I am by no means a messaging expert. I know SLC to SLC and CLX to SLC, but that’s about it’. No experience with the SLC EEM instruction.
I was sent a OneFex remote unit, 4 DI, 4 Relay-DO, 4 AI. They say it’s RTU over Ethernet, and I have it setup with their software - I can see the inputs on & off and the analog values, and turn the outputs on & off with their software over the network.
The first thing I would like to do is see if I can message this with a SLC5/05 to add to a machine, but haven’t been successful in getting it to be seen with my home 5/05 Ser E. Again: “No experience with the SLC EEM instruction.”
Do any of you with great messaging experience see how in the manual below to have a SLC see this, or if not possible how would a CLX see it so I can use it for something else.
The thing looks good quality and for the price it might turn out to be a deal - if they work. I don’t want resort to using the DH-485 port and run serial cables.
The module’s TCP protocol defaults to Modbus TCP, but it can also support Modbus
RTU over TCP, just select “Modbus Gateway” to OFF. That is, when ON is selected, it
is Modbus TCP protocol, and when OFF is selected, it is Modbus RTU over TCP
protocol.
But that seems to be for the DH-485 port, maybe the Ethernet port too??
I don’t know if it’s ETH or ETH/IP.
The only thing their saleslady said was these work with Allen-Bradley.
Browsed the manual, watched a couple of YouTube videos.
I do not think this will work with a SLC.
There looks to be an EDS file available, so you can use it with a CLX. The youtube video was very blurry, and difficult to follow the selections exactly.
A ML1400 should also work via Modbus TCP.
I guess you could use the Rockwell AOI, for Modbus on the CLX too. But I never liked that solution. Resource heavy, and not as reliable as I would like.
If you have any Red Lion gear laying around, they make for a great gateway between SLC and Modbus TCP or RTU devices. The SLC can make for a good Modbus RTU master, but lacks RS-485, so you’d have to use a RS-232 to RS-485 converter.
The ML1400 also is really good at Modbus, both TCP and RTU and has both types of serial ports, you just need a 1763-NC01 to easily access the RS-485 pins.
I have never used the Studio5k Modbus AOI, but have used the 5069-SERIAL Modbus RTU capabilities, and I am not a huge fan. There are no MSG instructions that support Modbus, rather it’s a table in the device configuration that requires a download to edit. It works great after you have it set up perfectly, and is zero based addressing which is the one thing I have messed up both times I have used one for Modbus. It has two channels and when used with any of the DF1 protocol variants, you can use MSG instructions which are easy to edit live.
Added the MODBUS to the ML1400 I have, added ONE MSG command to read inputs and immediately upon verification got memory used over 10K error message.
This thing has a small program in it running one floor lamp in security mode and reading 3 analog inputs and still had to delete half the program and reduce all the data files to the bare minimum just to get it to verify.
What’s going to happen when I try to read the analog integers and then write the coil outputs with 2 more MSG commands?
2 PC’s (1 Windoze / 1 Linux), my NAS, 2 printers, my X-box, my smart thermostat and my entire home automation setup of 5 PLC’s were ALL losing network and internet connection because that one cyclic MSG instruction was using at so much of my network resources and wouldn’t let anything else communicate.
Now I’m thinking of using the DH485 since I do have a DB-9 232/485 adapter and a DB-9 breakout to plug into it, then try some serial - but later when I want to play with that.
Still think it would be nice to have some SLC compatible Remote-IO stuff available since there are so many still out there and some customers still like them in new projects
That doesn’t make sense. I have multiple ML1400 telemetry programs, some of them polling up to 20 nodes with 40+ MSG instructions and none of them are “full”. String files are memory hogs, and I always pad out the data files with as twice as many spares as I think I will need. I have only rarely run tight on data file space and never gotten close to using up available program memory in a 1400.
As for bombing your network, that can be pretty easy to do if you have a MSG that fires as fast as the PLC can go. No need in doing that. Always regulate your MSG controls.
Forgive me if I misunderstood, I’m struggling to understand how ML1400 could pump out enough packets to overwhelm any network. An XBox would generate many orders of magnitude more traffic on a network. I mean, if a ML1400 sending out packets every 10ms, for example, takes down a network, how on earth would an XBox game of 60GB ever be able to update?
I’ve spent a lot of time using wireshark to debug pylogix, the amount of data any one controls device can generate is infinitesimally small compared to typical things on a home network (games, streaming, etc).
Again, sorry if I’m off and wasn’t following the plot.
It did, as soon as I turned off the message command everything else came back online. I also have a C-More HMI that was showing faults to all PLC’s during that time.
And it wasn’t a constant message command, it was triggered by a timer that I was going to use to read the analog inputs and write the outputs with 2 more MSG’s after I got the read working.
As for data files I don’t have any string or HTML files and only made one MG and one RI file for the one MSG.
Because it wasn’t working I didn’t save a copy of it when I opened the backup I had archived and redownloaded that.
