DirectsSOFT DL450 Messaging

[AMarks95]

I have some experience with DirectSOFT and can go online with PLCs, check data, change rungs, etc. etc., but I would definitely not say it's something I'm proficient in.

That said, in an existing system there are 5 different DL PLCs (DL454's and DL450's) that seem to send some information back and forth (a few bits here and there). I have no idea how the bits get from one PLC to the next, but I can see the bit in one PLC get set and never used (x-ref tree) and in the other I can see it used but never set.

For example, in one PLC bit nickname 'Bunker Destination Verify Bit' - C1722 is used 11 times, all in XIC/XIO instructions. In the other PLC bit nickname 'Bunker Destination Verify Bit' - C722 is only used once in an OUT instruction.

 

[Steve Bailey]

Search for the RX and WX instructions in the ladder logic.

 

[AMarks95]

Search for the RX and WX instructions in the ladder logic.

Is there a way to search for instructions, or do you mean look for it manually

 

[Steve Bailey]

You can search for instructions. Just hit <CTRL>+F and type the instruction name (RX or WX) into the search field that pops up.

 

[AMarks95]

You can search for instructions. Just hit <CTRL>+F and type the instruction name (RX or WX) into the search field that pops up.

Nothing found for 'RX' or 'WX'

 

[g.mccormick]

Is there an HMI or scada system involved at all? Is there a tertiary PLC that could be reading from PLC1 and writing into PLC2 (or the HMI or scada system doing the same).

 

[Steve Bailey]

Is there a network cable connecting all of the PLCs? Do any or all of them have an HMI panel attached?

And here's this comment from DL04 manual section on the RX and WX commands:
NOTE: If you are using a CoProcessor, Share Data Network, or DCM module,
please refer to their manuals for information on how to transfer data over the
DirectNET network.

 

[AMarks95]

Is there an HMI or scada system involved at all? Is there a tertiary PLC that could be reading from PLC1 and writing into PLC2 (or the HMI or scada system doing the same).

Definitely possible. There are a few PCs that I'll have to check.
Thanks for the insight.

 

[OkiePC]

These PLCs (actually the Ethernet interfaces) have a really cool means of setting up communications using what is called Peerlink. Use a web browser to access the Ethernet comm modules and poke around and see if Peerlink is in use.

 

[Dale87]

I'm not a master with direct soft by any means but generally you will see some LD (loads) which loads a value in the stack. Followed by an LDA which is the address then a wx for the write. It became simplified when ibox came into play on the newer software DS6. We have a facility that has several generators and a load shed program all in 454's. It's definitely different for people with an AB background. For me personally DirectSoft helps me justify spending the money on AB hardware and software. I asked AD how much longer they will continue supporting/selling the 454 platform, and they said they continue to sell a decent amount of them, although they did say they don't recommend them for new install......I'd look for some LD's LDA's and then a WX/RX all on top of one another in a rung..... Good luck is all I can say.....

 

[I_Automation]

The one thing to keep in mind is the RX/WX is probably only one ONE PLC reading from all and writing to all. If it is PLC based and not a HMI function as noted above.

That PLC should have a RX for each other PLC and a WX for each one also.
It can be limited in what it sends to each PLC, or send the entire folder of data to all PLC's

 

[bernie_carlton]

Yes, Peerlink is easy to set up for information sharing among multiple DL series CPUs. But, as noted, as it's totally contained in the Ethernet communication unit, it would be transparent when viewing just the PLC program. Good comments are necessary but if they aren't being viewed it could be a total mystery.