Invt CHV190-045G-4 [150/242] Communication protocol

CHV190 series special inverter for crane

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10. COMMUNICATION PROTOCOL

10.1 Interfaces

RS485: asynchronous, half-duplex.

Default: 8-E-1, 19200bps. Please refer to Group PC: parameter settings.

10.2 Communication Modes

(1) The protocol is Modbus protocol. Besides the common register Read/Write operation,

it is supplemented with commands of parameters management.

(2) The drive is a slave in the network. It communicates in ‘point to point’ master-slave

mode. It will not respond to the command sent by the master via broadcast address.

(3) In the case of multi-drive communication or long-distance transmission, connecting a

100~120Ω resistor in parallel with the master signal line will help to enhance the immunity

to interference.

10.3 Protocol Format

Modbus protocol supports both RTU and ASCII mode. The frame format is illustrated as

follows:

Modbus adopts “Big Endian” representation for data frame. This means that when a

numerical quantity larger than a byte is transmitted, the most significant byte is sent first.

RTU mode

In RTU mode, the Modbus minimum idle time between frames should be no less than 3.5

bytes. The checksum adopts CRC-16 method. All data except checksum itself sent will be

counted into the calculation. Please refer to section: CRC Check for more information.

Note that at least 3.5 bytes of Modbus idle time should be kept and the start and end idle

time need not be summed up to it.

The table below shows the data frame of reading parameter 002 from slave node address