I have SLC5/05 with ethernet port and want to communciate with a controllogix in 17 rack via seperately ethernt card Enet. In Controllogix I want to read data files from Slc500 by MSG instrument. The question is how to config the communciation path? or should I write a MSG instrument in SLC500 to write date Controllogix mapped data file? Thanks a lot!
MSG between SLC5/05 and Controllogix via ethernet
- Thread starter wilsonzhu
- Start date
Ken Roach
Lifetime Supporting Member + Moderator
This is quite straightforward once you think of the CIP Path as sets of Ports and Addresses, and understand that an IP Address, a Slot Number, and a ControlNet Node are all "Addresses". Port 1 is the backplane, and Port 2 is the Network.
RSLogix 5000 Help has the definitive article to which I always refer.
I think that you are describing a situation where you have a ControlLogix that can reach another 1756 chassis over Ethernet, but the SLC-5/05 is connected to that "bridge chassis" via a different 1756-ENET/ENBT/EN2T module.
The CIP Path goes from your controller to its local ENBT slot, then out Port 2.
The CIP Path then goes to the first 1756-ENBT module's IP address, then to Port 1.
The CIP Path then goes to the second 1756-ENBT module's slot, then out Port 2.
The CIP Path then goes to the SLC-5/05 IP address, then to Port 0.
The last "port" is fake; the SLC doesn't really have a backplane object.
If you need more help, describe the route your message has to take, using IP addresses and 1756 Slot numbers.
RSLogix 5000 Help has the definitive article to which I always refer.
I think that you are describing a situation where you have a ControlLogix that can reach another 1756 chassis over Ethernet, but the SLC-5/05 is connected to that "bridge chassis" via a different 1756-ENET/ENBT/EN2T module.
The CIP Path goes from your controller to its local ENBT slot, then out Port 2.
The CIP Path then goes to the first 1756-ENBT module's IP address, then to Port 1.
The CIP Path then goes to the second 1756-ENBT module's slot, then out Port 2.
The CIP Path then goes to the SLC-5/05 IP address, then to Port 0.
The last "port" is fake; the SLC doesn't really have a backplane object.
If you need more help, describe the route your message has to take, using IP addresses and 1756 Slot numbers.
MasterBlaster
Lifetime Supporting Member
What Ken posted is accurate. To address the second part of your question, the decision to use a READ or WRITE MSG instruction depends mostly on how fast you need the transmitted information to get to it's destination vs the network bandwidth you are comfortable with using. (You don't mention how much data must be exchanged.)
Consider the speed required and the network bandwidth consumed. A Write MSG requires more processor "housekeeping" than does a Read MSG. On the other hand, if speed is important, you can trigger a Write MSG to execute only when the condition in the "source" PLC changes. This is also known as "report by exception".
If you use a Read MSG in the "destination" PLC, you must trigger the Read frequently enough to detect the change in the source according to system response requirements. So, the "destination" PLC must constantly ask the source, "any changes yet?". This is not very efficient.
Just food for thought.
Bill
Similar Topics
A supplier is looking at fitting an SLC 5/03 with a NET-ENI module. I have seen this often, it is usually for Ethernet "enabling" an older PLC...
I'm using a SLC typed write from the ControlLogix5572 to the MicroLogix 1400, with path: 2, (MicroLogix IP). The ControlLogix equipment has a...
Hi all
I'm trying to setup a MSG connection (which I'm not familiar to) between a CompactLogix CPU (L310ER) and a Micrologix 1400 CPU. At the...
Anyone know if I can msg between a ControlLogix L71 (A) and an SLC5/05 (C) via backplane of second ControlLogix L71 (B)? ControlLogix (A) and SLC...
Hi,
Is it possible to write tag using MSG in two diffirent controllers in separated networks using Dual-IP? I need to do something like that:
1...