Introduction - Hitachi SJ7002 Series Instruction Manual

B–2

Introduction

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