Siemens SIMATIC Power Line Booster Operating Instructions Manual page 118

System configuration and system status (web interface)
6.5 Expert functions
To run the crosstalk measurement, you must first enter the IP address as well as the "admin"
password of the PLB master of the neighboring segment (remote master). Note that the
master on which you are logged in will set up a connection to the remote PLB master during
the measurement. If a connection setup to the remote master is not possible, check whether
a manual login has already permitted setup of a non-certified https connection. In addition,
no "admin" user may be logged in on the remote master during the measurement.
In the second step, you must first define the static parameters for the measurement. We
recommend using the values set for regular operation for "Transmit gain" as well as for "Limit
of dynamic receive gain".
Using the entry fields for the variable level, you can define the start and end value of the
measurement. In the first step, we recommend that you take full advantage of the full level
range. For later measurements you can limit the level range to reduce the measurement
time. We also recommend increasing the start value if no stable Powerline connection can
be set up between master and slave at the lowest level value.
When you start the measurement, all PLBs involved in the measurement (both masters and
both slaves) will run through the level values between defined start and end value
synchronously step-by-step. The cycle time in the segments is determined for each level
value and recorded in the graph. As soon as there is crosstalk, the cycle time in a segment
increases significantly. This is the crosstalk limit at which the powerline signal becomes
visible in the neighboring segment and thus prevents stable and deterministic
communication. The Power Line Booster can also evaluate the graph in case of a correct
measurement and displays the crosstalk limit for you as well as the currently configured
"static receive gain" of the four PLBs involved in the measurement.
Once you have determined the crosstalk limit at all segment intersections in the plant, you
must set the value with the highest/worst crosstalk limit as configuration for the "static
receive gain" on all Power Line Boosters in the plant.
With the standard configuration, there should be no crosstalk in a typical system. If this is not
the case, check the system installation (grounding of the PE rail, TC modules, shielding,
etc.).
Note that all long-term measured values of the Log tables (Page 85) are reset after the
crosstalk measurement.
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Operating Instructions, 11/2019, A5E36203125A-AG
Power Line Booster