Controlnet -

[waterboy 7]

Just discovered ControlNet... Had to add a module to a 3 rack cabinet and the racks are connected by controlnet. Slogged through the manual a bit and got to the point where the PLC must be put into Program mode to set the "schedule" and at this time I can't do that. I just wanted to know for sure that this is indeed required. Can someone confirm? I obviously need to get more comfortable with ControlNet, anyone know of a clear tutorial on it ? The Software seemed ok but doesn't help me understand how it works.

[dmargineau 6]

Unless the respective network has been originally deployed as an "unscheduled" type (very slight chances of that, especially for I/O!) you will have to put the CPU into Program Mode and re-schedule the network in order to accomodate any configuration changes.

[daba 4]

Is the module you are adding a Digital In or Out module ? Is the remote CNB set for Comm Format "Rack Optimisation" ? If the answer to both those questions is yes, then you will not need to reschedule the network, because the data transfer of the I/O data is buffered in the remote ControlNet Bridge (CNB) module, and that will already exist in the I/O tags exchanged with the processor. ergo - you will not actually be changing the volume or structure of the data being transferred, so the existing schedule is good to go. Analog modules do not use the Rack Optimisation function. However, If the remote CNB's connection comm format is "None", then you can still add the module (Digital or Analog) without re-scheduling the network. After inserting it into the configuration (online and processor running is fine), uncheck the "Use Scheduled Connection over ControlNet" box in the module properties "connection" tab, and the connection is not included in the "scheduled" part of the NUT (Network Update Time). Obviously you do not get the "determinism" of a scheduled connection, but the I/O will work. You can arrange to schedule the network at a later date when permissible - just tick the checkbox, apply, and the I/O LED will start to flash. The module properties will now be showing a "Connection Not Scheduled" error. Proceed with RSNetworx to re-schedule the network. Ask if you have any questions.... Edited 19 Apr 2013 by daba

[waterboy 7]

If I understand you correctly, I could leave it that way (unscheduled) and be fine forever? And if thats true and I don't care about precision I/O timing, does the CNB just become a way to "extend" racks? Any caveats to worry about ? I ask because I don't need deterministic timing in this application. I/O that gets acted upon in the same second or two is more than adequate. The CNBs came with the cabinet as a way to extend one rack into 3 (Lots of I/O here) and if I hear you correctly, All I really have to do is set the CNBs up and I can forget about the I/O modules.

[daba 4]

Yes - you could leave it that way... Yes and No - if you add another rack, the remote CNB will need scheduling if "Rack Optimisation" is chosen for its Comm Format. If you choose "None", and add any modules as "unscheduled" then Yes, it's just a "sloppy" I/O connection. " What makes the DO modules different? " - what output modules are you using, and what is the firmware revision of your controller, CNB modules, and output modules ???

[nodens 0]

I would like to join this topic and ask some question related to ControlNET.

 

How i should calibrate NUT and RPI times.

Case:

Right now NUT = 5msec

I have around 11 FlexIO adapters and eachone of them configured to RPI = 20 msecs.

Why 20? should it be 5*11 = 55 msecs? But in that case it works with 20.

So, how should it be and why?

 

Hope i explained myself enought to get an answer :)

Thanks in advance

 

EDIT:

Also for my understanding of NUT and RPI

NUT - each time interval CN receives/sends Values from/to IO

RPI - every interval IO adapter absorbs values from each Digital/analog card connected to adapter. 

Please correct me

Edited 28 Dec 2018 by nodens