Proface AGP3500 - 10.4 DIO HMI" - Manual (Page 73)

ST3000 Series Hardware Manual
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3.4.3 Interface Specifications
This section describes the specifications of each interface of the ST Series unit.
• The ST unit’s serial port is not isolated. 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 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 ST. 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.