Introduction
Appendix B
B–2
Introduction
SJ300 inverters have a built-in RS485 serial communications interface. This serial communica-
tions function provides a way of controlling from 1 to 32 inverters on a common serial network.
In a typical application, a host computer or controller is the master and each of the inverter(s) is
a slave, as shown in the figure below.
The specifications for SJ300 Series RS485 serial communications are in the following table:
Item Specifications User-selectable
Transmission speed 2400 / 4800 / 9600 / 19200 bps ✔
Communication modes Half duplex (one device transmits at a time) ✘
Synchronization Direct current transmission ✘
Character code ASCII codes ✘
LSB placement Transmits LSB first ✘
Electrical interface RS485 differential transceiver ✘
Data bits 7 or 8 bits ✔
Parity None / even / odd ✔
Stop bits 1 or 2 bits ✔
Start convention One-way start from host device command ✘
Wait time for response 10 to 1000 ms ✔
Connections Station address numbers from 1 to 32 ✔
Error check Overrun / Fleming block check code / vertical
or horizontal parity
✘
SJ300 SJ300SJ300
RS485 serial network
12 32