DL06 Networking

I am using DLO6's to controll my Solar collection systems at my home and shop. I want to "network" a few DL06's. one can be a master and others a slave. I am open to all options here. Final goal is to have my VB Program log data from each and allow me to send data out to make changes to one or two memory locations in each PLC.

Any help?

RS-485 I assume.

Not sure your question....it sounds like you know what you are doing, but I have done this over the Ethernet and it works very good, not with VB I'm using RSView, you may want to look at using Modbus on port 2

Using RS-485 you can have only 1 'master'. You may have to settle for the VB program being the master, coordinating everything, if you want it to directly communicate with all the DL06s. The ideal would be to use Ethernet as GIT proposes.

Thanks guys.

Clearing up my original question:

DL06's are located in several places and operate on their own, measuring temps, switching on pumps and valves as required.

I want to have my PC "poll" or "ask" each unit one at a time for several points of data, (total BTU's, Room temp, Array temp, valve status, etc.) then the PC will log and save all this information.

It would be ok with me if I set up a "master" DL06 to "ask" all the others and it would then save and "Print" the data out of a com port that my PC is wired too. Better option, Let the PC join the RS-485 network and be the "master".

Ethernet sounds great, but I used up all my slotts and really want more slots.

I also am thinking about a touch screen to allow house hold members to see the data as well as make some minor adjustments to the controllers.

Here are a few photos of the present set up.
I'm talking to each PLC via the ports, using a serial to ethernet converter. (one port for remote porgramming, one for data logging).

http://www.madpower.com/solar
(focus on thermal systems)

Thank you again for your help guys!!
Now that I'm thinking, Ethernet might be the best... Where I'm short on slotts, I could put two DL06's side by side.

JTE said:

It would be ok with me if I set up a "master" DL06 to "ask" all the others and it would then save and "Print" the data out of a com port that my PC is wired too. Better option, Let the PC join the RS-485 network and be the "master". .

Click to expand...

If you do use Ethernet you don't need a "master" like Berine said the VB would request the info or you could have the plc send the info to the VB 'on a change' in the process

I have a few DL06 programs where I do this over the Ethernet (that Berine and others helped me with) I can e-mail them to you if you would like, they may give you some ideas... I have to warn you..I write the programs for myself so my documentation sucks but I can read the code, I don't think you would have a problem

EDIT:if you want them send me a PM

JTE,

Since Enet seems out of the question, then you can network all your units using port 2 via 2 wire RS485. Then connect the PC to the master with port 1, (rs232).

The master would have a small bit of code that will poll the slaves and dump that info in memory reserved in the master. You can then look at that memory in the master to see the status of your slaves.

Note:

1) The master can directly control the Slave I/O, (no logic in the slaves). (significant operational latency).

2)OR the Slaves can have independent code and report only what's necessary back to the master. (little or min. operational latency).

Hi Elevmike,

When you say "No logic in the slaves" do you mean no code at all? IE a factory empty PLC?

Could my PC be connected to the Port2 Rs-485 link (I have RS-485 on my PC) and use my PC as the master? IE my VB program will poll each PLC and request only the preset memory locations.

Oh this is great stuff

Jim

When you say "No logic in the slaves" do you mean no code at all? IE a factory empty PLC?

Click to expand...

Yes you could do that, however if you loose the link, the outputs will retain the last status. If you go with the "dumb slaves", then you might have some code, (in the slaves) to detect loss of comm, and turn/force off outputs.

All you really need to get the salves operational is to configure the port to match the master port.

Could my PC be connected to the Port2 Rs-485 link (I have RS-485 on my PC) and use my PC as the master? IE my VB program will poll each PLC and request only the preset memory locations.

Click to expand...

Not sure but dont think so. You would connect the PC to the RS 232 on the master and poll the master with your VB app.

JTE,

Personally if a little bit of latency is not a problem, then I wouldnt bother with E-net. Simply for cost considerations. The ports are there on the PLCs already.

Each e-net module will cost you $175 - $200. If youre networking 5 units, that's $1000.00 + additional slaves etc... The issue is how much latency can the applicaion tolerate, and how much that's worth to you.

JTE said:

Hi Elevmike,

When you say "No logic in the slaves" do you mean no code at all? IE a factory empty PLC?

Click to expand...

I believe you need an "end" statement to get the plc into run mode

--------------------------------------------------------(END)

Good programming practice would also include setup parms for the #2 port. See Bernie Carlton's site http://www.theplcguy.com/Modbus/hooking_up_6.htm
If you include the #2 port setup parameters in the logic then If you have to replace the plc no further setup is required. Just load the logic and your done.