Rockwell Automation 57C570 AutoMax PC3000 User Manual - Manual (Page 190)

18Ć8
Registers Description
Registers 32 Ć 39
(Broadcast Data)
The master transmits the data in its broadcast registers to
the broadcast registers in each slave Network module
simultaneously each time it updates a drop area. This is
done every 2.99 milliseconds (the time it takes to update
one drop area). The data in the broadcast registers is not
targeted for any particular drop. Controlled by the
application task running in a Processor module in the
master rack, broadcast data is usually data of higher
priority that needs to be transmitted to all drops as soon
as possible, such as emergency stops, line speed
references, and network status. These registers are
Read/Write in the master and Read Only in the slaves.
18.3.2 Assigning Variables to the Data Exchange
Registers
Drop areas 1Ć55 are divided into 64 16Ćbit data registers. Registers
0Ć31 in drop areas 1Ć55 contain the data that an application task in
the slave rack has written to them. These registers will then be
transmitted to the master and all other slaves on the network. The
number of registers that an application task in that rack can write to
is determined by the drop depth assigned to the PC3000. Each
slave has 32 registers times its drop depth that can be written to and
then transmitted. In other words, a PC3000 that has been defined as
drop 01 with a drop depth of 2 has Read/Write access to registers
0Ć31 in memory drop areas 1 and 2 for a total of 64 registers. This
area is Read Only everywhere else on the network.
Registers 32Ć63 contain the data that an application task in the
master rack has written to the master DCSĆNET network interface for
a particular drop. This data is consequently transmitted from the
master to the addressed drop with all other drops receiving the data
simultaneously. The master has 32 registers times the number of
drops on the network to write to and then transmit. This area is
Read/Write in the master and Read Only everywhere else on the
network.
The dual port image of registers 32Ć39 in the drop 0 area and drop
areas 1Ć55 will be the same in each module that is active on the
network. Therefore, the data in all drops which are active on the
network are available to any other drop that is active on the network.
A time lag will exist between output data written from one drop and
its appearance in the dual port image of all other drops. This time
lag will be less than or equal to the update period as described in
chapter 3.