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3. Overview
RS-232C, RS-422A, RS-485 are available in communication interface of KP and are used for
communication with personal computer (hereinafter referred to as PC).
PC can receive measurement data from KP, various parameters can be set and operation commands
can be issued. Number of KP connections is 1 for RS-232 and maximum 31 for RS-422A, RS-485.
3-1. RS-232C communication interface
RS-232C is the data communication standard set and executed by Electronic India Alliance (EIA) and
Japanese equivalent for that is JIS C 6361.
This standard is basically an interface with modem and data terminal device connected to it and only
electrical and mechanical specifications are given.
Presently RS-232C communication interface that is used in industrial instruments like PC and DB
series, only some of them completely conform to the above standards, and signal wire count and
connectors for connection etc. may sometimes differ from the standards.
As nothing is specified about the software part or what we call 'data transmission procedure' it does not
mean that the devices that RS-232C communications interface can be connected unconditionally.
Hence, it is necessary that the designer investigates and confirms the specifications and transmission
procedure of the mutual device. However if the connection partner is able to program those specifications
optionally like the PC, the designer, by creating the appropriate program, can combine it with almost all
the devices.
When investigating the RS-232C standards, the method of referring to JIS C 6361 is the simplest
method.
3-2. RS-422A/485 communication interface
RS-422A/485 communication interface can communicate by connecting in parallel the KP series of a
number of machines (maximum 31) through the signal that conforms to RS-422A/485.
PCs that have RS-422A/485 communication interface are less however as it is a serial communication,
connection can be easily done by using RS232C RS-422A/485 signal converter.
Line converter (Our company model: SC8-10) for RS-232C RS-422A/485 signal conversion is
available with our company. You may order it from us.
Difference between RS-422A and RS-485 is that RS-422A uses 4 signal wires whereas RS-485 uses 2
signal wires.