Can CCW use Ethernet I/P to 3rd party devices?

[Gene Bond]

I can't seem to find an answer in Rockwell's site or here. I am curious if CCW can connect to 3rd party devices via E-I/P like other brands and Studio 5000 can.

I am not an AB guy by any means. I refuse to enter into a subscription software agreement out of principal. But, from time-to-time, customers want support on their applications, and I am willing to invest in some hardware and a bit of time to learn enough to get them going. So, if they support it, I'll pick up a processor, risk my computer by installing their software, and work out some E-I/P mapping for test purposes...

 

[PreLC]

I'm going to limit my answer to using Micrologix 1400 PLCs with CCW.

According to Rockwell's KB, the Micrologix PLCs only support explicit messaging for EIP. If your IO/EIP Device supports Explicit messaging, it can work with CCW.

QA7177:

Question
What Ethernet protocol does the MicroLogix 1400 use and are there any restrictions that should be considered?

Answer
The Ethernet communication channel, Channel 1, allows your controller to be connected to a local area network for various devices providing 10 Mbps/100 Mbps transfer rate. MicroLogix 1400 controllers support Ethernet/IP with CIP explicit messaging (message exchange), BOOTP/DHCP Client, HTTP Server, SMTP Client, DNS Client, SNMP Server, Socket Interface with CIP Generic messaging, Modbus TCP Client/Server and DNP3 over IP. MicroLogix 1400 controllers do not support Ethernet I/O master capability through CIP implicit messaging (real-time I/O messaging).

Note: SNMP support is minimal for the MicroLogix 1400. It is limited to the setting and reading (GetRequest and SetRequest) of a limited number of simple variables such as SysContact and SysLocation. Device information is also available from the SysDescr variable.

 

[Gene Bond]

Thanks for that. I guess I forgot that there are multiple methods of Ethernet I/P communications...

I am used to using AD's Ethernet I/P functions, which appear to be Explicit. The assemblies for Input and Output, Message Size, Data Type, Number of Elements, etc. I believe this is referred to in some instances as an I/O Scanner? I know it is not real-time, though it is more reliable (IMO) than Modbus. This is what I am after. I use it for connecting drives typically.

Also, I am considering the Micro 800 series PLCs.

 

[Ken Roach]

"Explicit" network communications includes the function of the packet inside the packet itself. Explicit messaging is typically done over TCP/IP and is slower and non-cyclic. Message (MSG) instructions are used to execute messages as programmed in the user application.

"Implicit" network communications infers the function of the packet from a connection identifier. Implicit messaging is typically done over UDP, often on a cyclic timer repeating every few milliseconds. Connections are configured in a controller's "I/O Tree" and are created and managed automatically by the network module, daughtercard, or subsystem.

Assembly numbers, fixed data sizes, and defined formats of packed data are all typical of Implicit I/O connection communications.

Allen-Bradley PLC-5, SLC-500, MicroLogix, and Micro 800 controllers are all only capable of explicit communications on Ethernet.

Allen-Bradley ControlLogix and CompactLogix support both explicit and implicit communications over Ethernet.

There are some exceptions and workarounds that complicate the distinction, like the ability of A-B variable frequency drives accept an explicit SLC-500 style data table read/write command to control the drive, a function that would otherwise require an implicit cyclic I/O connection.

Micro 800 controllers that do connect to VFDs and single-axis servos generally use User-Defined Function Blocks that are meant for that one specific product. A-B does a pretty good job of documenting them, but it's not prudent to extrapolate "I can control a PowerFlex 525 with a Micro 850, so I must also be able to control a Yaskawa V1000 with a Micro 850".

I'm not an Automation Direct user; can you give an example of which controllers support cyclic EtherNet/IP communications to devices like distributed I/O and VFDs ? Are those set up with function blocks in the user program, or configured in something like an "I/O tree" or "Scanlist" ?

 

[pturmel]

The Productivity series of Automation Direct processors all support Ethernet/IP as either master or slave or both together. All by configuration without function blocks. The connections may have large buffers, similar to the E/IP support in Omron and Keyence products. (~1440 bytes each way, IIRC, versus 500 in Rockwell products.)