5
5. Universal Serial Communications 5-5
Connections
5. Universal Serial Communications
• A general purpose computer or an ASCII unit of the PLC (master station) controls the POD (slave
station) using dedicated commands.
• The UG230 internal user memory addresses ($u) must be used for memory allocation for switch,
lamp or data display parts.
When the master station specifies a screen number, data is written to the internal memory address
($u) allocated for the screen. If the screen is switched internally, the new screen number is read
and is written to the internal memory address ($u) allocated for the screen.
• For 1 : 1 connection, the UG230 can send an interrupt to the master station through switch
activation, write command from the keypad, and screen change.
• Use MJ2 (or CN1 when the UG230A-DCL is provided) of the UG230 for connection with a
general-purpose computer. Either signal level RS-232C or RS-422 (RS-485) can be selected.
• In addition to 1 : 1 connection, 1 : n connection is available between the general-purpose
computer and the UG230 via RS-422.
(A maximum of 32 UG230 units can be connected.)
For 1 : n connection, interrupts cannot be used.
• For more information, refer to the User’s Manual <PLC Connection> (FEH380).
RESET
disc
MJ2
RS-232C or RS-422 (RS-485)
UG230
Write
General-purpose
computer
Dedicated commands
Interrupt
Read
RESET
disc
MJ2 MJ2 MJ2 MJ2
RS-422 (RS-485) connection
UG230 1
General-purpose computer
UG230 2 UG230 3 UG230 n (n = 1 to 32)