Sending UDP messages to a video player

Hey guys. This is my first time delving into UDP commands, at least from a PLC standpoint.

My setup is as follows; Productivity 2000 PLC; BrightSign LS422 media player.

The BrightSign is setup to receive UDP messages on port 5000 at it's local IP. I've tested and verified that it is working by using a simple UDP terminal. When I send "UDPTEST" to it, it plays the video file.

What I'm completely lost on at this point is even where to begin on the PLC. I've attached a screenshot of what I'm presented with when I add the "WX" Network Write command. I was hoping it would be as simple as making a string tag with "UDPTEST" in it and specifying an IP and port, but it does not appear to be so. I created a string called "UDPTEST" with the initial value of "UDPTEST" and tried to use it by clicking on the "String" radio box at the bottom of the instruction box. I can put the "UDPTEST" in the "String Tag of this project" box and set it to "number of characters = 7", but it returns an error saying I must also use "String tag of remote project". That box is greyed out and does not allow me to put any value in it.

Any help would be much appreciated!

I have found no information about using the Productivity 2000's Ethernet port for UDP messaging. I only see Modbus TCP to other Productivity units or as an Ethernet/IP adapter.

What is your source for using it as UDP?

bernie_carlton said:

I have found no information about using the Productivity 2000's Ethernet port for UDP messaging. I only see Modbus TCP to other Productivity units or as an Ethernet/IP adapter.

What is your source for using it as UDP?

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Bernie, according to the reps at AD that I've spoken with, it can do it. There is a bit in the manual about it as well, though it doesn't give any instruction. I would also further assume that since in the box it allows you to assign "GM-01" (the onboard ethernet port) to the instruction, that it can be done. There is a separate ethernet port onboard specific to Modbus TCP for a different network.

All I see about UDP is being the base protocol for Ethernet/IP. I'll try to look into it a little farther.

The dialog screen is clearly for modbus tcp or modbus RTU communication. (modbus tcp is using tcp port 502)
There is no way you can do UDP communication using that.

"UDP" would be similar to saying "serial". It doesn't say anything about what you are sending, just the way you do it. So this has to be done in the program, with blocks or some kind of programming. The only thing you could possibly configure in a dialog is the ip address and UDP port of media player you are going to communicate with.

Unless AutomationDirect provides a LOT more information I don't see any way of sending a raw UDP message from the Productivity system.

I had a look at the communication manual for that PLC.

I'd say there is no way you can send anything over UDP, or TCP for that matter. It only supports fixed protocols over ethernet (modbus tcp, ethernet/ip, plc to plc communication).


So yes, you can communicate over UDP and TCP but only with those protocols that it supports. So you can't just send whatever you like.


The media player has it's own commands so you can't communicate with it over the ethernet port.

On serial however you have the Custom Protocol Functionality. The commands are CPO and CPI and allows you to send and receive anything.

The media player seem to have a serial connection so you could use that instead. If it absolutely has to be over ethernet you need more hardware in between.

Link to user's manual - communications
http://www.automationdirect.com/static/manuals/p2userm/ch6.pdf


PS. Bernie was saying the same thing but I didnt see his post before sending my own.

Pete.S. said:

I had a look at the communication manual for that PLC.

I'd say there is no way you can send anything over UDP, or TCP for that matter. It only supports fixed protocols over ethernet (modbus tcp, ethernet/ip, plc to plc communication).

So yes, you can communicate over UDP and TCP but only with those protocols that it supports. So you can't just send whatever you like.

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Unless it is referred to differently in the PLC world, "ethernet/ip" *is* TCP/UDP data. In any other industry (and I come from a background in IT), if you say ethernet, you're pretty much saying TCP/IP communications. UDP is just a protocol that runs over ethernet.

The media player has it's own commands so you can't communicate with it over the ethernet port.

Click to expand...

They aren't specific protocol commands. They're whatever you want them to be. IE, "UDPTEST" was a string that I made up. It isn't a dictated command. The player will absolutely communicate over ethernet, I have that working without issue. I just need the PLC to spit it out.

On serial however you have the Custom Protocol Functionality. The commands are CPO and CPI and allows you to send and receive anything.

The media player seem to have a serial connection so you could use that instead. If it absolutely has to be over ethernet you need more hardware in between.

Click to expand...

The player will work over serial, however it's RS232. As the players are already on the network to receive updates, I'm trying to not have to run additional serial cables across the facility (especially RS232. And 232 > 485 addressable converters are expensive).

I'll give AD a call on Monday and see what they say again. I'm not yet convinced that the "network write" command can't send on the same local network.

Ethernet/ip is NOT a generic name for ethernet communication (like for instance ethernet or tcp/ip).

It's a fieldbus (spelled correctly it's EtherNet/IP):
https://en.wikipedia.org/wiki/EtherNet/IP

Why use a PLC?
Be better to use something that can sent UDP messages a lot more easily.
Trying to do something so specific from a PLC is just more hassle than it worth for something like this. (IMHO)

lostcontrol said:

Why use a PLC?
Be better to use something that can sent UDP messages a lot more easily.
Trying to do something so specific from a PLC is just more hassle than it worth for something like this. (IMHO)

Click to expand...

There are plenty of PLCs that can send generic UDP traffic with no issue. If you're controlling everything else from one place, it makes sense to control other devices from there as well. However, when you pick your PLC platform before you know what your needs are, then it can become a huge limitation.

If you have a serial port free for use, you MAY be able to use a device such as a Lantronix serial to Ethernet converter. You'd write your "UDPTEST" string to the serial port and the Lantronix would craft your UDP datagram for the media player.

I would use a RedLion datastation +

I called AD today. Even the rep there was a bit confused on if it can do UDP messaging. It looks like it can, but only, as was brought up earlier over EtherNet/IP. I'm going to see if my device will still accept it as a multicast packet. In my head, UDP is UDP, regardless of the transport, but I'm likely wrong on that.

Worst case scenario, I will have the PLC's spit out ASCII over RS485. I'll use a Raspberry Pi to intercept the RS485 ASCII, convert it and spit it back out over the network as UDP that my BrightSign can understand. The code to do that on a RPi should be fairly trivial.

A simple 232 to Ethernet adapter. Use a raw ASCII message.