Toshiba RS-485 - Manual (Page 5)

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1. Overview
By using RS-485 Option Unit, a network can be constructed that allows communication between a host
computer and multiple ASD units. A maximum of 32 Option Units can be connected on the same
network. And two ASDs can be connected to one Option Unit. A maximum of 64 ASDs can be connected
on the same network. (If ASD has a CPU whose version is V104 or V103, a maximum of 32 ASDs can
be connected on the same network.)
2. Communication specifications
Item Specifications
Interface Conforming to EIA RS485 standard
Configuration 4-wire, bus type (terminating resistor is necessary at
each end of system)
Communication Distance 1,000m maximum
Connection Points 32 units maximum
Number of ASDs per one Option Unit 2 units maximum
Number of ASDs on the Same Network 64 units maximum (If ASD has a CPU whose version
is V104 or V103, a maximum of 32 ASDs can be
connected on the same network.)
Communication Line Isolation Not isolated
Synchronization Method Start-stop synchronization
Error Detection Method Parity, checksum
Communication Speed 1200/2400/4800/9600 baud selectable (parameter
and switch selection)
Data Code ASCII code, binary code
Other Time-out function available