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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3.4
Communication toward meters
3.4.1
The right communication speed
After the right IP address has been established the M-Bus loop’s communication
speed has to be adjusted. The communication speed adjusted in the Wizard has to
match the meters communication speed. Many meters have a communication
speed of 300bps at delivery. If there is a possible to set the meters at 2400bps try
to do that in order to increase the communication speed and by that improve the
performance.
When communication toward the meters has been established and by that the M-
bus loop is connected the right way, you can continue to configure the superior
software.
3.4.2
Adjusting the meter’s communication speed
In version 1.0 of the M-Bus Wizard you can control the meter on your M-Bus loop
directly via the meter’s primary address. You can also adjust functions such as
communication speed and primary address via your network. Note that some
meter makes do not support the possibility to change for example the primary
address via a standard M-Bus command.
3.4.3
Manufacturer specific configuration software
If you want to configure the meters via the meter delivery’s own software you can
do so in most cases over the network via the gateway. They usually have no
network support, so they communicate only via the communication port on the
computer. By using Comport Redirector, described in chapter 8, you can usually
use this software in your network.
3.4.4
Important parameter adjustments
Some issues to keep in mind regarding communication between the meter and the
superior software is the time interval between the questions, the number of
telegram that can be read by the meter, and what communication speed that has
been chosen. Some meters has up to 40 telegrams that can be read at a adjusted
transference speed of 300bps, and therefore take along time.
The M-Bus driver for the SCADA program Citect, which has been developed by
PiiGAB, is documented with great details
regarding
how
different
parameters are being set in programs like NrOfTelegrams, InitRead etc. The
document “Citect for Windows, Version 5.xx, 6.xx M-Bus driver, User Information”
(Version: 1.01.03.001-1) is available to download at the PiiGAB website.