Rockwell E/IP Instance Datatypes

Not a Rockwell guy, but will be setting up a Yaskawa controller to work with a ControlLogix PLC via Ethernet/IP. The Yaskawa controller can mix datatypes, but it appears that the Rockwell side can't. Is that true? If I want to send DINT's and REAL's, do I have to put them in different instances? Using both Implicit and Explicit messaging in the application.

On the Rockwell side, if you developed a UDT for the transfer, you can mix data types in the UDT. I often create UDT's like this for produced/consumed tags in CLX. Have 10 DINTS, followed by 20 Reals for example.

Highland:
Last week I made my first interface with yaskawa A1000 drive and CompactLogix.
It had messages and AOI, if you want a copy just let me know your email via PM.

Originally posted by Highland Controls:

The Yaskawa controller can mix datatypes, but it appears that the Rockwell side can't.

Click to expand...

This is correct. Any given generic I/O instance will need to use all the same data type for the instance.

Ken Moore talks about the way I usually handle this kind of thing. However, you will need to use a COP or CPS to get the I/O data into the UDT. The Logix processors don't support the concept of a union. The MOV instruction will preserve the value of a tag across datatypes, which you don't want. A COP is a byte-for-byte copy of one memory area to another. This is what will allow you to put the bit pattern of a REAL into a DINT and get it back into a REAL.

You can do this same thing element by element without the UDT but the UDT method takes care of the whole data set in one instruction.

Keith

Thanks widelto, but this is a Sigma7iec controller/servo drive. I am not handling the Rockwell side at all.

Is it an ordinary Sigma7iec drive, or the "SigmaLogic 7" version ? SigmaLogic is a lot more tightly integrated with Rockwell than the IEC controllers.

In general a cyclic I/O connection can be a block of one datatype, and an MSG instruction can use a payload of one datatype.

A common workaround is (as posted) to "pack" data bytes into the other data type and "unpack" them on the other side. This has been a solution (and a headache) on all platforms for decades, as anyone who has transferred a floating-point value in a Modbus register can tell you.

Sigma7iec, which can mix data types with no problem. I will work with the Rockwell programmer to see what our options are.