Omron MX2 Inverter RS-485 Connection Guide

The Destination Device (inverter) reported an unsupported function was specified in the Modbus command. This indicates that the Modbus function code sent by the master device is not recognized or implemented by the inverter, leading to command rejection. Such an error prevents the desired operation from being executed by the inverter.

The Destination Device (inverter) reported that the specified register address does not exist within its memory map. This means the Modbus command attempted to access a register address that is not allocated or supported by the inverter's Modbus communication data list, preventing data access.

The Destination Device (inverter) reported that the data specified in the Modbus command is in an unacceptable format. This can occur when writing data that does not conform to the expected data type, length, or structure for the target register, resulting in the inverter rejecting the data.

The Destination Device (inverter) detected an attempt to write data to a holding register where the value is outside the permissible operational range. This prevents the inverter from accepting the value, often to protect itself from invalid settings or unsafe operation, such as setting an over-limit frequency or an excessively low acceleration time.

The Destination Device (inverter) rejected a function or write command because its current operational state or configuration prohibits the requested action. This is a protective mechanism, preventing changes that could interfere with active operations like RUN, auto-tuning, or changes to locked parameters (e.g., during Undervoltage conditions).

The Destination Device (inverter) rejected a write command because the targeted register is designated as read-only. This fault occurs when the Modbus command attempts to alter a parameter or status value that the inverter only permits to be read, not written, thereby protecting internal state and configurations.

This error indicates that the CMND instruction failed due to a problem communicating with the destination node, specifically a response timeout. This means the destination device (e.g., inverter) did not respond within the configured timeout period, preventing the CMND instruction from completing successfully.

This error signifies that the command sent by the CMND instruction has an incorrect format or structure, preventing the communication unit from processing it correctly. This indicates a malformed FINS command, where the structure of the data sent does not comply with the expected protocol.

This status bit, when active (1), indicates that a general communication transmission error has occurred through the Serial Communication Unit (SCU) port 1. It serves as an umbrella flag for more specific communication issues such as FCS, timeout, overrun, framing, or parity errors, preventing successful data exchange with the destination device.

This status bit, when active (1), indicates that the parity check performed on the received data frame failed. This means the count of '1' bits in the data did not match the expected parity (even, odd, or none), signifying data corruption during transmission or a mismatch in parity settings between the devices.

This status bit, when active (1), indicates that the received data frame did not terminate with a valid stop bit, leading to a loss of synchronization. This is a common issue when the data bits or stop bits settings are mismatched between the communicating devices, or if there is significant line noise causing signal distortion.

This status bit, when active (1), indicates that the Serial Communication Unit's (SCU) receive buffer overflowed because incoming data was received faster than the SCU could process it. This typically points to a mismatch in transmission speed or a processing bottleneck, leading to loss of received data.

This status bit, when active (1), indicates that the Serial Communication Unit (SCU) did not receive a response from the Destination Device within the expected time frame. This suggests either the Destination Device is not responding, is too slow to reply, or the response message is not reaching the SCU, causing the communication attempt to fail.

This status bit, when active (1), indicates a Frame Check Sequence (FCS) error was detected in the received Modbus message. This means the integrity check (CRC16) of the received data failed, suggesting that the data frame was corrupted during transmission due to noise or mismatched communication settings, leading to unreliable data.

This error indicates a problem with the communication unit itself or the CPU bus, preventing the CMND instruction from executing properly. This is often a hardware or configuration issue with the serial communication unit (SCU), affecting its ability to communicate with the PLC CPU.