Do-more EtherNet/IP Explicit Messaging Primer from AutomationDirect

The do-more plc supports ethernet/ip messaging so it can configure and query any ethernet/ip device out there that supports the ethernet/ip explicit messaging protocol and it can be set up as Nathan IP slave to your existing system or it can do both at the same time now there's a lot of terminology you got to wrap your head around with this explicit unconnected messaging so before we do live examples let's take a look at the big picture this video covers all these concepts in other videos we have live demos showing you step-by-step exactly how to use unconnected explicit ethernet/ip messaging to configure control and monitor Ethernet IP devices for the purposes of this video let's assume we use a do-more is the client and in allen-bradley Powerflex 40 variable frequency drive as this server and that the Powerflex 40 Drive is equipped with the Ethernet adapter module to make it Ethernet IP compatible Appendix C of the Ethernet adapter manual summarizes everything we need to know about how to access the data in the Powerflex 40 drive via ethernet/ip the first table in appendix break stuff up into these objects an object is just a generic way to describe things that share common features or attributes we'll look at the details of these specific objects in the next video where we do a live example with the power flex 40 drive for now if we look at objects in general and we use the example of drive parameters the drive parameters all have similar attributes right each parameter has a name of value a min a max a data type etc these are all attributes we can use to describe each of the drive parameters so we can use a template like this to describe each parameter here's Drive parameter 31 for example with his values filled in his name is current value etc keep in mind I'm just making these numbers up for now we'll look at real data in the next video here's another one parameter 32 the motor nameplate frequency again uses the exact same template and just fills in the blanks how about parameter 39 acceleration time same thing parameter 40 deceleration same thing so we end up with a huge group of tables like this describing every parameter in a drive using this common attribute template which we call an object now what can I do with these tributes well I can get the value set the value reset the value etc we call those services all the things you can do to this common set of objects so since all these instances of this common template or object share a common set of attributes and services we group them together into a common class of objects we call this the parameter class now there's one more template that we need this one describes the attributes of the class itself it tells us the revision of this class the total number of parameters in this class and some other things we might want to know about this group or class of objects so again the template describes a generic object and a filled-in template creates a single instance of the object like parameter 31 that's an instance of the object here's another instance another instance another instance so suppose for a moment we want to get the value of parameter 31 well we look up at the manual and we find out that the parameter class is number 15 or 0f hex the get code is 0e the instance of this object that we want is number 31 parameter 31 and the attribute we want is number 2 the value we simply hand those numbers to the explicit message instruction and it fetches the value of that parameter for us the cool thing about this is since every Ethernet IP drive uses the exact same messaging with this exact same set of templates you can use this exact same instruction at any Drive not just this one so once you understand how to use this all the sudden your world just got a whole lot bigger because you don't have to learn a new way of accessing every new device it comes down the line you just specify an Ethernet IP enabled device and the code you wrote for one manufacturers device will be easily ported over to any other manufacturers device that's huge and it makes you much more productive now each class has its own set of predefined tables but you access each one the same way for example let's look at the identity class this is used to identify different components in a device in our device we have the host drive itself and the Ethernet adapter you might even have another communications adapter module connected to the drive how would you get the vendor ID or the device type or the revision of the serial number well you would use this identity class here's the predefined template of attributes now the vendor just fills in the blanks to create an instance for each object here's the drive instance so I can now go look up all these things about the drive here's the ethernet/ip adapter instance and again you might have some other communications modules the drive manufacturer will create one of these instances for every option available and since they all use this standardized template along with a standard list of services and class attributes anyone that wants to know about the identity of one of these objects knows how to get it you as a programmer just issue a command that says you want to get from identity class the revision of the host drive we'll see how to get those numbers in the examples in the next video but given these numbers we just issue an explicit message command and ethernet/ip messaging retrieves the revision of the hardware for us if you're super ambitious you can even write a program to query and fully auto detect and configure an entire Ethernet IP system without knowing anything but the IP address of each device on the network because you can ask every device who he is what type II is and then configure him appropriately very cool what other kinds of classes of objects are there that is groups of things that behave similarly well if we look at that allen-bradley VFD for example it looks like there's an assembly object or register object and a whole bunch of others do you need to know all of this now in fact most of the time all you're gonna care about is the parameters object so you can set up and configure the drive will do several examples of that one and maybe a couple others in the next video the key thing about this is once you get the hang of using these classes of objects you'll be able to use them with any Ethernet IP enabled device out there that includes other manufacturers drives encoders remote i/o other PLC's and packs etc and of course the do-more enable controllers make it super easy to do well that ought to be enough to get you oriented check out the other videos in this series to see some live demos of the do-more using explicit unconnected messaging to communicate with devices like the allen-bradley power flex drive and how to set the do-more itself as an ethernet/ip slave if you need any help please contact automationdirect's free award winning tech support during regular business hours they'll be happy to help and don't forget the forum's there are lots of folks there that to share their years of experience just don't post any questions for automationdirect's support staff there they don't monitor the forums on a regular basis spend less do more with automation direct