Chapter 11 RS485 Communication
11-3-4
Error handling of Modbus mapping function
If there is an error in Modbus mapping setting, an exceptional response of the following
exception code is returned. If an exceptional response occurs, review the external register
settings or internal register settings.
・The external register has been set, but the internal register has still been "0000" (default).
・"2 register length parameter" is set in the internal register.
・A holding register number that does not exist at the internal address was set.
・The external register settings are duplicated.
・Both of the higher and lower bits of "2 register length parameter" was set to the external
register and either one of the bits was accessed. ((Example 1) in the figure below)
As shown in the figure below (Example 1), if the higher or lower register number of the inverter
internal register of "2 register length parameter" is mapped as an external register, access to the
register number that has not been set will result in an error.
In the figure below (Example 1), the external register is set to 1103h, and the internal register
1107h is accessed. However, because 1103h is the high-order register number of "Acceleration
time setting 1, 1st-motor [F002]", accessing the low-order register number 1104h results in an
error (exception code "32h").
When the register number already used inside the inverter is set as an external register as shown
in the figure below (Example 2), the inverter internal register cannot be accessed. (Setting
1204h to the external register disables access to the conventional "Maximum frequency, 1st
motor".)
Modbus mapping
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