CLX MSG to PLC5 over serial - octal or decimal and more :)

Partial disclaimer: I'm not the one programming the radios so everything is suspect. But I need to get the CLX eliminated as a problem.

I will be looking through the CLX docs on this more thoroughly in a minute (glancing didn't provide results on serial comms that weren't modbus) but if anyone knows the answers off the top of their head...

I am trying to make a CLX communicate over radio with a PLC5 using only the CLX serial port. And failing.

The target PLC5 is connected to it's radio via serial port and Ethernet but most PLC5's I have to convert wont have Ethernet so I am focusing ONLY on that.

I have succeeded with an ML1400 at a different location to MSG this target PLC5 over the radio using both Ethernet and Serial, and both in sequence together so I'm confident in the target PLC5 and Radio as well as the host ML1400 and its radio. At least as far as having the ML1400 initiating the conversation. . . .

The CLX and its radio is in question.

1st - does the CLX MSG addressing use octal address or decimal (2,43 or 2,35)?(using PLC5 Typed read)
2nd - how firm is the 50 foot serial cable limit, that seems short by serial standards. I have much more than that.
3rd - Radio is MDS Orbit MCR. single AP and multiple Remotes. the working radio is the AP to one of the remotes with the AP initiating every message. I wonder if the remotes can initiate communication. seems silly that they wouldn't be able to.

TheWaterboy said:

1st - does the CLX MSG addressing use octal address or decimal (2,43 or 2,35)?(using PLC5 Typed read)

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Keep its node ID 0 to 7 and you don't have to guess. I have not done any serial comms with Logix5k so I am not sure.

2nd - how firm is the 50 foot serial cable limit, that seems short by serial standards. I have much more than that.

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For RS-232, I have gone 75 feet without issue, in metal conduit away from sources of noise. I have tried 100 feet and failed (had to add a signal extender).

3rd - Radio is MDS Orbit MCR. single AP and multiple Remotes. the working radio is the AP to one of the remotes with the AP initiating every message. I wonder if the remotes can initiate communication. seems silly that they wouldn't be able to.

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I don't think they should, but I am not sure that they cannot. You only want one device sending on that frequency at any time, so over the air (with few exceptions) communication is half duplex, with the "master" and slaves taking turns with requests and responses.

I have done a few systems where is was necessary to have one master and one or two "sub-masters" in which I let the slave take control to poll nearby units and then send the response back to the master, but this was with radio modems that did not have any designation as "AP", "master", etc. With radios that can be set up as a specific role, you might need to set up more than one as the "master" role in order to allow them to take turns initiating messages in such a manner.

OkiePC said:

Keep its node ID 0 to 7 and you don't have to guess.

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Not an option here, got more than that to hook up.

For RS-232, I have gone 75 feet without issue, in metal conduit away from sources of noise. I have tried 100 feet and failed (had to add a signal extender).

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I've probably got just under 200 feet. I know I have run 1000 feet for other serial applications, but they were slower.

I have done a few systems where is was necessary to have one master and one or two "sub-masters" in which I let the slave take control to poll nearby units and then send the response back to the master, but this was with radio modems that did not have any designation as "AP", "master", etc. With radios that can be set up as a specific role, you might need to set up more than one as the "master" role in order to allow them to take turns initiating messages in such a manner.

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I may in fact have to do that, I have already set up a timing sequence between 2 hilltop locations using existing microwave infrastructure that I'm hoping I don't need to use. The one hilltop and the low freq looks like it will cover the area from an RF perspective.

But I gotta get the CLX talking first, its the poll master. Support thinks is an Store and Forward problem. I'm skeptical but the AP is on hilltop and the poll master PLC is on a slave so . . .

Well now, is this interesting. My MSG is set up with Local node address of 35, and it is actually communicating with address 80... Time to start sniffing traffic I think.