T H E M O D E R N M - B U S T E C H N O L O G Y
PiiGAB Process Information i Göteborg AB
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Com Port Redirector
8
8.1
Introduction to Com Port Redirector
8.1.1
Overview
Com Port Redirector is a software utility for network-enabling legacy software
applications that do not have network support. Com Port Redirector installs virtual
Windows
®
communication ports. These virtual communication ports are redirected
over a network to the M-Bus port of a PiiGAB 810 Gateway.
The communication with the gateway is done in pretty much the same way as
when ”pure” TCP/IP is used. The main difference is that the software sees the
gateway as a normal communication port.
Figure 8-1 Example how Com Port Redirector works when 810 is used
In most cases, legacy software that uses the virtual com ports created with Com
Port Redirector encounters no problems and acts as if it were communicating with
a physical port. Not all software applications, however, are suited for use with Com
Port Redirector.
Serial port software applications are designed for direct communication with the
serial device being managed. However, when device servers are used across a
network, latency can occur with the connection from the software to the managed
810 gateway. Some software applications have timing constraints for data
transmitted and received on com ports. In some cases, a software application will
not wait long enough to receive a response from the 810 gateway being managed.
As a result, the software assumes the serial device is not responding and times
out.
Should increased latency become an issue for a software application, implement a
TCP socket connection in the software. If this is not possible, increase the timeout
settings in the software to compensate for additional latency.
Chapter
8