9
3.
Grounding Cautions
• Be sure to create an exclusive ground for
the Power Cord’s FG terminal. Use a
grounding resistance of 100
Ω
, a wire of
2mm
2
or thicker, or your country’s applica-
ble standard.
• The SG (signal ground) and FG (frame
ground) terminals are connected internally
in the ST (except for COM2 on the
AST3211-A1-D24) unit.
When connecting the SG line to another
device, be sure that the design of the sys-
tem/connection does not produce a short-
ing loop.
• The grounding wire should have a cross
sectional area greater then 2mm
2
. Create
the connection point as close to the ST unit
as possible, and make the wire as short, as
possible. When using a long grounding
wire, replace the thin wire with a thicker
wire, and place it in a duct.
4.
Input/Output Signal Line Cautions
• All ST Input and Output signal lines must
be separated from all operating circuit
(power) cables.
• If this is not possible, use a shielded cable
and ground the shield.
To prevent the USB cable
from coming off
Attaching the USB Holder
(1) Before starting the procedure, lift up the
tab on both sides of the USB Holder and
remove the USB Cover.
(2) Attach the USB holder to the USB Host
Interface part of the main unit. Hook the
upper pick of the USB holder to the
attachment hole of the main unit and
then insert the lower pick as shown
below to fix the USB holder.
ST unit
Other
Equipment
Exclusive Grounding
(BEST)
ST unit
Other
Equipment
Common Grounding (OK)
ST unit
Other
Equipment
Common Grounding
(Not OK)
Tab
USB Holder
Attachment
Hole
