Ethernet MSG with GE MDS ECR Radios

Has anyone had experience using UHF (451/456MHz) Ethernet Radios to successfully MSG between Allen-Bradley PLCs (SLC 5/05 and ML1100s)? The system I'm upgrading has used serial radios on that frequency and the DF1 Radio Modem mode of Channel 0 for years. I installed it a decade ago.

My customer has FCC licensing for 451MHz & 456MHz so the new GE MDS ECR "Ethernet" radios use both frequencies for full-duplex TX/RX so they "mimic" hard-wired Ethernet media. I'm skeptical since initial tests show high latency with simple pinging between a Master and the Repeater – 1200mS to 2700mS. Forget about MSG instructions executing so far. That’s why I’m posting this.

For the upgraded system, my customer leases space at a hilltop County radio site which provides Line-Of-Site paths for every new radio. The new radio system has two rack-mounted "Masters" that transmit to a "Repeater" at the County radio site; from there, all the stations all over the City should have great communications. No site (30 overall) is more than 5 miles LOS to the Repeater so receive signal levels are near saturation.

GE and the Manufacturer’s Rep that the radios were purchased thru claim most of their install base is Allen-Bradley PLC SCADA systems. So it should work right out of the box. However, I see no application notes, white papers, mention on bulletin boards etc. anywhere online. The GE guy asked if I was using DF1/Ethernet. WHAT?! First of all, I don’t even know what that is. Secondly, why would my customer spend all this money to gain Ethernet wireless comms for their PLCs to be pointed in the DF1 direction? The new radios only have RJ45 ports. No standard serial com ports for system usage.

What am I missing?

read this first. https://literature.rockwellautomation.com/idc/groups/literature/documents/um/ag-um008_-en-p.pdf.

then tell us the model number of the radios (master and remote)

I have.
Downloaded, read and saved in 2007 just before I put in the existing serial modem system that is being replaced.
Not relevant to today's technology/application.
Thanks for the tip anyways.

GE MDS Orbit Master/Repeater Stations: MPRL4ERD4G1S2G33FULNN (3 EA.)
GE MDS Orbit Remote Stations: ECRL4ENNNNNS1S1USUNNN (30 EA.)

Have you looked at these? https://www.youtube.com/channel/UCWEcxa9_FSdEqowzxNbNLsw.
I am assuming the SLC-5/05 is your half duplex master and the ML-1100 are the slaves.
The ML-1100 The Ethernet communication channel, Channel 1, allows your controller to be
connected to a local area network for various devices providing 10 Mbps/100
Mbps transfer rate. MicroLogix 1100 controllers support CIP explicit
messaging (message exchange). MicroLogix 1100 controllers do not support
Ethernet I/O master capability through CIP implicit messaging (real-time I/O
messaging). Have you tried to set up a message from the SLC to the ML-1100 over the Ethernet channel?

I have dealt with a handful of UHF Ethernet radios (not the GE MDS, but have viewed work done by others) and I still prefer simple serial radio modems. There simply isn't going to be enough bandwidth on the UHF to allow you to do things like go online with RSLogix to a remote PLC while polling messages are still enabled. I mean ... technically you can, and while you wait for the software to complete the upload of data, you can get in your truck and drive over to the remote location about as quickly.

So your changes will be to move your message logic to the Ethernet channel and there are a few items of importance. In some Ethernet radios, the IP config of the radios must be on the same network as the PLCs...have a plan for your IP scheme that is sensible and accounts for all the devices that will be on that same network. If possible, separate the radio, PLC and HMI IP scheme from other stuff.

Ethernet messages by default will have a timeout setting that is way longer than you will want if you are using a typical round robin messaging pattern...you don't want to wait 33 seconds for a MSG/ER bit before going to the next step in your polling. What I do is run a program on power up that sets the Message Timeout Value (MGx:y.MTO in Micrologix) to 3 to 5 seconds for all the message data blocks in use. That way I can leave the Ethernet channel timeouts at reasonable values and not have to add separate logic to my polling routine for monitor each message for a timeout. This makes it look and act more like serial messages.

I have also read recommendations to turn off duplicate IP address detection where possible. Apparently that feature can add unnecessary TCP traffic.

I have left my PLC channel set to auto-negotiate without problems when using Xetawave radios. I inherited a system that had them all set for half duplex using CalAmp Viper radios. That system eventually got "downgraded" to a far more reliable and faster polling serial radio modem and I donated the Vipers to an SI that probably has more luck or more IT guru skill and can make them work better.

The other thing to bear in mind is that all the radios will have unique configurations, where most serial radios can be set identically in all locations, especially if you use the same frequency for transmit and receive on them all. So any spare radios will either need to be accounted for in your IP scheme and programmed accordingly or someone with the tools and skill to set them will have to do that as the need arises. With our favorite serial radio modem, we set them all the same and the customer only needs to know how to operate a screwdriver to perform a replacement.

My experience with the GE MDS modems was good. I didn't design or program them, just did a little troubleshooting and found them to be solid and documentation was good, the model I worked on used a web browser for config and is was as good as the others...