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Appendix B
ModBus Network Communications
B-1 Introduction
MX2 Series inverters have built-in RS-485 serial communications, featuring
the ModBus RTU protocol. The inverters can connect directly to existing fac-
tory networks or work with new networked applications, without any extra
interface equipment. The specifications are in the following table.
I
The network diagram below shows a series of inverters communicating with a
host computer. Each inverter must have a unique address, from 1 to 32, on
the network. In a typical application, a host computer or controller is the mas-
ter and each of the inverter(s) or other devices is a slave.
Item Specifications User-selectable
Transmission speed 2400/4800/9600/19.2 k/38.4 k/
57.6 k/76.8 k/115.2 k bps
✓
Communication mode Asynchronous ✕
Character code Binary ✕
LSB placement Transmits LSB first ✕
Electrical interface RS-485 differential transceiver ✕
Data bits 8-bit (ModBus RTU mode) ✕
Parity None/even/odd ✓
Stop bits 1 or 2 bits ✓
Startup convention One-way start from host
device
✕
Wait time for response 0 to 1000 msec. ✓
Connections Station address numbers from
1 to 247
✓
Connector Terminal connector –
Error check Overrun, Framing block check
code, CRC-16, or horizontal
parity
–
Cable length 500m maximum
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