Introduction
Append
ix
B
B–2
Introduction
SJ700
2
inverters have a built-in RS485 serial communications interface. This serial communi-
cations function provides a way of controlling from 1 to 32 inverters on a common serial
network. SJ700
2
, SJ300, and L300P inverters all have the same communications prototol. 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 SJ700
2
Series RS485 serial communications are in the following table:
RS485 serial network
1
2
32
SJ700
SJ700
SJ700
Item
ASCII Mode
ModBus RTU mode
User-selectable
Transmission speed
2400 / 4800 / 9600 / 19200 bps
✔
Communication modes
Half duplex (one device transmits at a time)
✘
Synchronization
Start/stop transmission
Asychronous transmission
✘
Character code
ASCII code
Binary code
✘
LSB placement
Transmits LSB first
✘
Electrical interface
RS485 differential transceiver
✘
Data bits
7 or 8 bits
8 bits
✔
Parity
None / even / odd
✔
Stop bits
1 or 2 bits
✔
Start convention
One-way start only by command from host device on network
✘
Wait time for response
10 to 1,000 ms
0 to 1,000 ms
✔
Connection format
Station address numbers from 1 to 32 maximum
✔
Error check
Overrun, framing, BCC, vertical
parity, and longitudinal parity
errors
Overrun, framing, CRC-16, and
longitudinal parity errors
✘