- What is a
communication processor?
- Why is a
Liaison communication processor a better choice than a protocol converter or
other specialized device?
- Do Liaison
communication processors support proprietary networks?
- Do Liaison
communication processors handle redundant Ethernet? Other redundant
network connections?
- What does
multi-channel communication refer to?
- Can Liaison
communication processors serve as OPC clients and/or servers?
- Can I do
configuration, monitoring and diagnostics over a LAN, the Internet or
Dial-in connection?
- How secure
is it?
- Do Liaison
communication processors support wireless, telephone and fiberoptic media?
- What is
the difference between an S3 and S5?
- Is the
configuration, monitoring and diagnostic software compatible with Microsoft
OS?
It is device that is both
specialized (for industrial data communication) and generalized in the
sense that it encompasses the capabilities of several single-function
communication devices such as protocol converters, routers, multiplexers,
concentrators, special-purpose interfaces, etc... Liaison
communication processors are designed to provide users with a single
intellectual investment that provides them with a wide and expanding array
of communication capabilities.
First, communication links are
often necessarily the last element considered in any project and it is the
unexpected considerations that make the flexibility and power of the
Liaison communication processors a valuable tool. Liaison technology
was created in response to our experience in commission on-site
links. The economic considerations of a communication link extend
well past the capital equipment expenditure. Commissioning time,
time required for troubleshooting and support all have significant value,
usually far more than the rather minor expenditure for the
equipment. Liaison communication processors provide extensive
diagnostic and monitoring capabilities, many of which are usually only
found in high-end RTUs (including remote monitoring, diagnostics and
configuration).
Secondly, Liaison communication
processors provide a wider range of options for dealing with unforeseen
and unknown elements of a communication link. User-defined functions
can produce programmatical behaviors on for a single data point (scaling,
byte-swapping, etc...) to accommodate virtually any requirement.
Beyond the internal resources, the software architecture is designed to
make modification and development of protocol drivers in a fraction of the
time normally associated with such actions for more traditionally
architected communication products. Added command functions, support
for additional command sets, and complete custom driver development can be
conducted in days and weeks were it used to take weeks and months.
The combination of Liaison equipment, services and support produces
a total system for commissioning communication links.
Finally, the power, flexibility and
expanding capabilities inherent in Liaison communication processors makes
it far more sensible as an intellectual investment than learning the ins
and outs of a hodge-podge of equipment from different vendors and of
varying quality and capability.
Where possible. Some
protocols specifications are held very closely. Liaison has the
capability to reverse engineer various protocols when asked and if not
legally constrained. Other protocols are supported by license, which
usually means there is an extra cost involved. For other proprietary
protocols with available specifications, Liaison will develop drivers are
a very reasonable cost (made possible by the software architecture that
allows extremely rapid development--ask for a quotation)
The independent function of each
network client makes redundancy easily implementable by simply configuring
an identical second network module and associating it with another port (a
second serial or Ethernet port...). Since each network module
interfaces with the daemon and not with each other, it is possible to
produce a 'Y' link where a single channel connection is split over
redundant buses, or between two redundant buses.
Liaison communication processors
can be configured with a variety of port configurations; multiple serial
ports, multiple Ethernet ports, multiple specialty interfaces like
Profibus and/or DeviceNet. Each generalized port (Ethernet, serial)
can be independently assigned a communication protocol. For example,
if you had 6 serial ports available, each serial port could be assigned to
use a different driver or multiple modules of the same driver (Modbus for
example). You could conceivably use a single communication processor
to exchange data between a Modbus port, an AB DF1 port, a GE SNP port,
etc... With the use of an appropriate Ethernet switch, a single
Ethernet port could run multiple Ethernet protocols, such as Modicon
TCP/IP, AB CSP (PLC5e) Ethernet and Ethernet IP (Controllogix).
Any Liaison communication processor
can be configured with any type and number of network modules for which
physical ports are available on the device.
Not at the moment, although such
functionality is currently under development.
Yes. Liaison communication
processors supports native TCP/IP Ethernet and a variety of internet
protocols. It also appears as a native device on Microsoft networks,
which means that you can "explore" the device as if it were a
network drive. All the familiar functions of Windows Explorer can be
used to drag & drop or copy and paste files between the communication
processor and any other device on the network.
Command functions are accessible
using telnet or SSH protocols.
Additionally, the diagnostic and
monitoring functions are available through your web browser with an
intuitive graphical interface. Browse maps, data point values,
counters and various logs.
Liaison communication processors
conform to the requirements of the ISO 17799 Information Security
Protocols. It features multi-level security access to the device
software, the use of encrypted protocols and other features necessary to
implement a robust security policy. Its important to understand that
the presence of security functionality is not the same as applying it
within an overall system designed to address security comprehensively.
Yes, although not through a
built-in port in every case. Liaison communication processors
support internal modems for dial-in and dial-out capabilities, wireless
communication in the form of spread spectrum, frequency hopping or WIFI
technology. Currently, no internal fiberoptic ports are available.
The S3 is a compact, DIN mounted
unit, while the S5 is a panel mount model with far greater resource
capacity. For example, an S3 supports a maximum of 10 serial ports,
while the S5 can support hundreds. The S5 comes standard with dual
Ethernet ports and can accept both ISA and PCI interface cards when
appropriate. Configuration follows precisely the same outline for
either model.
There is in fact, no configuration
software, microsoft or otherwise. The monitoring, diagnostic and
configuration software is actually a Java application that loads to the
browser (either IE or Netscape). An up-to-date Java plug-in is
required and is available free from Sun (a link to the upload page is
available under the support menu). Configuration files in comma
separated variable format (.csv) and compatible with Microsoft
Excel. Both the S3 and S5 can be mounted as network drives under
Windows Explorer allowing drag and drop and other conventional
file-handling methods.
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