Devicenet Command again

Dear all
i am implementing a IO slave module .i have 4 output points which are
monitored by 4 discrete output point objects .An assembly object has a
output instance which shall monitor these 4 Discreteoutput point
objects (as i understood from specs).in the specs the attribute of the
assembly object is a byte array .I have a doubt that what will be the
master command format inorder to invoke this assembly object.will
master send the bytes or bits (in a single byte) as the values for the
assembly object attribute . i am not able to make out the exact format
of the frame sent by the master for a assembly object to set the
values for Discreteoutput point objects monitored by it
plz correct me if i am doing in a wrong way 
regards 
PMM

"pmm" <muralipmanohar@hotmail.com> wrote in message
news:1f1fe31f.0404262135.7d76e1e8@posting.google.com...
> Dear all
> i am implementing a IO slave module .i have 4 output points which are
> monitored by 4 discrete output point objects .An assembly object has a
> output instance which shall monitor these 4 Discreteoutput point
> objects (as i understood from specs).in the specs the attribute of the
> assembly object is a byte array .I have a doubt that what will be the
> master command format inorder to invoke this assembly object.will
> master send the bytes or bits (in a single byte) as the values for the
> assembly object attribute . i am not able to make out the exact format
> of the frame sent by the master for a assembly object to set the
> values for Discreteoutput point objects monitored by it
> plz correct me if i am doing in a wrong way
> regards
> PMM

Typically, a master device communicates with slave devices
via one of the Predefined Master/Slave Connection set (PMSCS)
connections such as Strobe, Poll, or COS...
These are I/O connection in which the meaning of the data is
implicitly defined by the connection.  This is oppossed to
explicit messaging where the meaining of the data is explicitly
spelled out within the message itself.
Since the meaning of the data within the I/O connection is
implicitly defined, the message is often just the data itself,
without any extra information.  If you want to transfer four
bytes of data over an I/O connection then the message format
probably just needs to be those four bytes of data, one right
after the other.  (If you need to transfer more than eight
bytes within an I/O connection then you must split the data
accross more than one CAN packet and use the first byte of
each packet for the fragmentation protocol.)

The CAN connection IDs of the PMSCS connections are predefined
in the DeviceNet specification.

Typically, you determine at design time the content and format
of the data your slave will exchange with the master.  You
also determine which PMSCS connection(s) your slave will use.
The decision on which connection(s) to use depends on the size
of the data and the manner in which you want the application
data to be transferred.
If you want to send 4 bytes of data from the master to the slave
in a periodic fashion then the Poll connection might be for you.

For the slave's I'm familiar with, an Assembly Object instance
is used to model the content and format of the data sent via
each PMSCS connection.  Think of the Assembly data as the slave's
local copy of a connection's data.  The slave code is written
so that when the PMSCS message is received the data is copied
into the data buffer for the associated Assembly instance.  Or
when a PMSCS message is sent the data is copied from the data
buffer of the associated Assembly instance.  Since the Assembly
data is a collection of parameters from other Objects, your
slave code will also copy or somehow link the data to those
other objects as well.

I apologize if I strayed from your question but I hope this
helps.

 -- Kevin

"Kevin Kramb" <kekramb.invalid@ra.rockwell.com.invalid> wrote in message news:<1090pfbamj8p3da@corp.supernews.com>...
> "pmm" <muralipmanohar@hotmail.com> wrote in message
> news:1f1fe31f.0404262135.7d76e1e8@posting.google.com...
> > Dear all
> > i am implementing a IO slave module .i have 4 output points which are
> > monitored by 4 discrete output point objects .An assembly object has a
> > output instance which shall monitor these 4 Discreteoutput point
> > objects (as i understood from specs).in the specs the attribute of the
> > assembly object is a byte array .I have a doubt that what will be the
> > master command format inorder to invoke this assembly object.will
> > master send the bytes or bits (in a single byte) as the values for the
> > assembly object attribute . i am not able to make out the exact format
> > of the frame sent by the master for a assembly object to set the
> > values for Discreteoutput point objects monitored by it
> > plz correct me if i am doing in a wrong way
> > regards
> > PMM
> 
> Typically, a master device communicates with slave devices
> via one of the Predefined Master/Slave Connection set (PMSCS)
> connections such as Strobe, Poll, or COS...
> These are I/O connection in which the meaning of the data is
> implicitly defined by the connection.  This is oppossed to
> explicit messaging where the meaining of the data is explicitly
> spelled out within the message itself.
> Since the meaning of the data within the I/O connection is
> implicitly defined, the message is often just the data itself,
> without any extra information.  If you want to transfer four
> bytes of data over an I/O connection then the message format
> probably just needs to be those four bytes of data, one right
> after the other.  (If you need to transfer more than eight
> bytes within an I/O connection then you must split the data
> accross more than one CAN packet and use the first byte of
> each packet for the fragmentation protocol.)
> 
> The CAN connection IDs of the PMSCS connections are predefined
> in the DeviceNet specification.
> 
> Typically, you determine at design time the content and format
> of the data your slave will exchange with the master.  You
> also determine which PMSCS connection(s) your slave will use.
> The decision on which connection(s) to use depends on the size
> of the data and the manner in which you want the application
> data to be transferred.
> If you want to send 4 bytes of data from the master to the slave
> in a periodic fashion then the Poll connection might be for you.
> 
> For the slave's I'm familiar with, an Assembly Object instance
> is used to model the content and format of the data sent via
> each PMSCS connection.  Think of the Assembly data as the slave's
> local copy of a connection's data.  The slave code is written
> so that when the PMSCS message is received the data is copied
> into the data buffer for the associated Assembly instance.  Or
> when a PMSCS message is sent the data is copied from the data
> buffer of the associated Assembly instance.  Since the Assembly
> data is a collection of parameters from other Objects, your
> slave code will also copy or somehow link the data to those
> other objects as well.
> 
> I apologize if I strayed from your question but I hope this
> helps.
> 
>  -- Kevin

Hello Mr Kevin
I have read spec couple of times ,bu8t even now i am landing to confusion 
thanks for your Message i will read spec again :-)
have a nice day
PMM