Communicating with the PLC
6.2 MODBUS communication
SINAMICS V20 Inverter
Operating Instructions, 07/2012, A5E03728167
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The table below shows the cases in which an Exception Code is returned:
Error description
Exception Code
Unknown Function Code
01
Read registers, which are out of boundary
02
Write register, which is out of boundary
02
Read request of too many registers (>125)
03
Write request of too many registers (>123)
03
Incorrect message length
03
Write to a read-only register
04
Write register, error in parameter access
04
Read register, error in Parameter Manager
04
Write to a zero entry
04
Unknown error
04
Basic inverter settings
Parameter
Function
Setting
P0010
Commissioning parameter
= 30: restores to factory settings
P0970
Factory reset
Possible settings:
= 1: resets all parameters (not user defaults) to their default
values
= 21: resets all parameters and all user defaults to factory
reset state
Note: Parameters P2010, P2021, P2023 retain their values
after a factory reset.
P0003
User access level
= 3
P0700
Selection of command source
= 5: USS / MODBUS on RS485
Factory default: 1 (operator panel)
P2010[0]
USS / MODBUS baudrate
Possible settings:
= 6: 9600 bps
= 7: 19200 bps
= 8: 38400 bps (factory default)
...
=12 115200 bps
P2014[0]
USS / MODBUS telegram off time [ms] By default (time set to 0), no fault is generated (i.e.
watchdog disabled).
P2021
Modbus address
Sets the unique address for the inverter.
Range: 1 ... 247 (factory default: 1)
P2022
Modbus reply timeout [ms]
Range: 0 ... 10000 (factory default: 1000)
P2023
RS485 protocol selection
= 2: Modbus
Factory default: 1 (USS)
Note: After changing P2023, powercycle the inverter.
During the powercycle, wait until LED has gone off or the
display has gone blank (may take a few seconds) before
re-applying power. If P2023 has been changed via a PLC,
make sure the change has been saved to EEPROM via
P0971.