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