5. CONFIGURATION
Configuration Description Default Options
Communication Time-out
(ms)
Defines the application level
time-out
3000 10 to 65535
Maximum Number of Re-
tries
Defines the numbers of re-
tries before reporting a com-
munication error
2 0 to 9
Table 86: Device Configurations
Notes:
Slave Address: According to the MODBUS standard, the valid slave addresses are from 0 to 247, where the addresses
from 248 to 255 are reserved. When the master sends a writing command with the address configured as zero, it is making
broadcast requests in the network.
Communication Time-out: The communication time-out is the time that the master waits for a response from the slave
to the request. For a MODBUS RTU master device it must be taken into account at least the following system variables: the
time it takes the slave to transmit the frame (according to the baud rate), the time the slave takes to process the request and the
response sending delay if configured in the slave. It is recommended that the time-out is equal to or greater than the time to
transmit the frame plus the delay of sending the response and twice the processing time of the request. For more information,
see Communication Performance section.
Maximum number of retries: Sets the number of retries before reporting a communication error. For example, if the
slave does not respond to a request and the master is set to send three retries, the error counter number is incremented by one
unit when the execution of these three retries. After the increase of the communication error trying to process restarts and if
the number of retries is reached again, new error will increment the counter.
5.5.5.1.3. Mappings Configuration – Symbolic Mapping Settings
The MODBUS relations configuration, showed on figure below, follows the parameters described on table below:
Figure 58: MODBUS Data Mappings Screen
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