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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
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