AB Redundant Network & Redundant HMI

[p.ghasemi 0]

Hello every body, I have a redundant pair plc-5/30 allen bradley system(BCM), and 4 plc-5/20 system. Now i want to design a monitoring project for them by RS-veiw. I have a question, how can i have 2 OWS and one EWS in my monitoring configuration with following constraint: 1- I want to use 1784-PKTX card in my PC 2- I want to have redundancy in my network (Cabling) and monitoring system Thanks

[kaiser_will 65]

DH+ is your choice for communication, as you probably know. Are the PLCs networked today or are they stand-alone? If they are stand alone, before connecting you will need to declare their DH+ node addresses and they all need to be unique; refer to the DH+ manual (node address 1-74, I remember). I typically make the PC node 1. Refer to the A-B DH+ Installation Manual. http://literature.rockwellautomation.com/idc/groups/literature/documents/um/1770-um022_-en-p.pdf Typical DH+ communication cable is Belden #9463. http://www.belden.com/products/industrialcable/data-highway.cfm Research the DH+ plan, plan your network, DH+ address your PLCs, purchase and install the DH+ cabling. I suggest getting communication going to one PLC at at time. I rememeber you need a pull up resistor at the end of your DH+ networks (i.e., at your PC assuming it is the end and at the last PLC end). You can call or chat with Allen-Bradley/Rockwell during US central time M-F 8a-5p. http://www.rockwellautomation.com/rockwellautomation/support/get-support-now.page? DH+ is rock solid for PLC comms, in my opinion, and has been around for a very long time. There is a lot of tech support literature on the web for DH+.

[p.ghasemi 0]

Hello dear sparky, Thanks for your attention to this matter. My PLCs are stand alone. You sent me an useful document. I want to make a redundant cabling for my Backup system what is your suggestion to this issue.I'll attach a picture that mainly describe my plan. I have two major issues,one is making redundant HMI system and another is making a redundant network. In this picture I think I solved the first Issue, am I right? and please guide me to solve those issues. Best Regards Edited 19 Oct 2014 by p.ghasemi

[kaiser_will 65]

It appears to be a good DH+ network plan. Suggest you phase in one PLC first, bringing other PLCs on one at at time. As long as you can see all nodes in RSLinx, you can rest assured connection is good. Remember the termination resistors at both ends of your DH+ network. You will have no communication or intermittent communication is both are not present.

[MrAutomation 20]

Another option is to replace them all with PLC-5/40E cards and use ethernet. This is a little more expensive or course.

[p.ghasemi 0]

Hi, Thanks very much. As you said replacing with Ethernet CPU makes it expensive. How about using another CPU with Ethernet & DH+ capability in higher level? it make us possible to communicate with DH+ devices by Ethernet network. what is your opinion?

[MrAutomation 20]

Sorry about the delay in the comments. Yes I've seen a ControlLogix rack used in this method before. Put a 1756-EN2T (or 1756-ENBT) and a 1756-DHRIO module on the same backplane. No CPU required. This becomes your bridge between Ethernet and DH+ networks, and you can browse through the DHRIO module to DH+ network in RSLinx. It works great. Edited 5 Nov 2014 by MrAutomation