Proface AGP3500 - 10.4 DIO HMI" - Manual (Page 37)

ST3000 Series Hardware Manual
3-6
3.1.3 Interface Specifications
This section describes the specifications of each interface of the ST Series unit.
• The serial interface of the ST Series (except AST-3211A COM2) does not have
an isolation function. When the host (PLC) unit is also not isolated, be sure to
connect Pin #5 SG (Signal Ground) terminal to reduce the risk of damaging the
RS-232C/RS-422/RS-485 circuit.
• ST Series (except AST-3211A COM2) have the SG (signal ground) connection
and the FG (frame ground) connection inside. When connecting an external
device to the ST using the SG terminal, be sure to check that no short-circuit loop
is created when you setup the system.
• The same type of connector is used for COM1 and COM2 of the AST-3201A. Be
careful not to mistake one for the other. Connecting them incorrectly disables
communication.
• Connecting the RS-232C isolation unit (CA3-ISO232-01) to COM1 enables isolation if
needed.