User manual

Publication LOGIX-AP010B-EN-P - May 2010 113
Communication and Networking Chapter 6
The Logix 1756-SYNCH module uses fiber optic links to transfer data at high
speed from one controller chassis to multiple chassis. The high speed data
transfer makes it particularly suitable for applications that require data to be
transferred at a high speed and in a synchronized manner. Such applications
may include distributed motion control and coordinated drive control
applications where the rate of data transfer between networked nodes is
critical. The SYNCHLINK modules transfer data unidirectional. Therefore
they cannot serve as a replacement for communication cards, for example,
EN2T, when exchanging data with remote I/O cards.
S5 CP 580 & CP 581 Communication Processor Modules
Although these modules are referred to as communication processors they are
mostly used in conjunction with S5 controllers to provide additional
computing performance. Direct communication between these modules and
the S5 controller takes place via the S5 backplane. These modules are suitable
for tasks that require a sizable amount of data handling, such as analyzing
and/or processing data or the storage of recipe data. This frees up processing
capabilities in the S5 controller. These modules also contain the MS-DOS
operating software that allows MS-DOS commands from the S5 controller to
activate programs for execution on the CPU 580.
The additional processing power available in the Logix controllers as
compared to the S5 controllers means that all the required processing can now
be done in the controllers. Multiple Logix controllers can be placed in the
same rack or distributed in remote racks to provide as much processing
capacity as required.
The relative cost of computers and servers has decreased since the 1980s.
Their storage capacity has greatly increased, and the speed and reliability of
data transfer also has improved. This means that extensive data storage can
now be easily and cheaply achieved by connecting a computer/server to the
controller via an Ethernet card, and using the computer/server to store data
that can then be monitored by using a SCADA application such as FTView.