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General outlines of the communication function – Toshiba Tosvert RS485 User Manual

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1. General outlines of the communication function

This manual explains the RS485 communication function provided for the TOSVERT VF-AS1 series
of industrial inverters.

(1) RS485 communication by the use of a two-wire RS485 communication port (standard function)
(2) RS485 communication by the use of a four-wire RS485 communication port (standard function)

By using these communication functions in combination with the computer link function designed to
establish a link between a higher level computing machine or controller (hereinafter referred to as a
computer) and each inverter on the network, or with the inter-drive communication function that al-
lows proportional control of inverters without using a computer, you can set up a network for data
communication between inverters.

There are two communication protocols available: Toshiba Inverter Protocol and MODBUS-RTU
Protocol (this command does not support all commands). To select a protocol, the communication
protocol selection parameter f807 or f829 is used. (Refer to Section 3. Communication proto-
col.)

By preparing the program (explained later), the following information can be exchanged between the
computer (host) and the inverter.

(1) Monitoring function (used to monitor the operating status of the inverter: Output frequency,

current, voltage, etc.)

(2) Command function (used to issue run, stop and other commands to the inverter)
(3) Parameter function (used to set parameters and read their settings)


Master inverter sends the data, that is selected by the parameter, to all the slave inverters on the
same network. This function allows a network construction in which a simple synchronous or
proportional operation is possible among plural inverters (without the host computer).

As for data communication codes, the TOSVERT VF-AS1 series of inverters support the binary
(HEX) code, in addition to the JIS (ASCII) code. A communication number is used to access the de-
sired data item.

* The smallest unit of information that computers handle is called a “bit (binary digit),” which repre-

sents the two numbers in the binary system: 1 or 0. A group of 16 bits is referred to as a “word,”
which is the basic unit of information the VF-AS1 series of inverters use for data communication.
One word can handle data items of 0 to FFFFH in hexadecimal notation (or 0 to 65535 in decimal
notation).

BIT15

BIT8BIT7

BIT0

1 bit

1 word

(1) 2-wire RS485 communication

connector

(2) 4wire RS485 communication

connector

This manual is related to the following products: