NT31C-ST143-EV3 Omron, NT31C-ST143-EV3 Datasheet - Page 145

• Manufacturer Part Number: NT31C-ST143-EV3
• Description: 5.7 8-Color Dsp,STN,Ivory,Eng
• Manufacturer: Omron

Specifications of NT31C-ST143-EV3

• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Connecting to the Host’s RS-422A/485 Port
5-2-8
128
Handling the Shield on RS-422A/485 Cables
Reference:
1,2,3...
Note
Before connecting or disconnecting cables between devices, make sure that
the power supply to all of the connected devices (NT31/NT31C, PLC, etc.) is
OFF.
Perform the following procedures to connect, process the shield, and connect
to ground for communications systems using the RS-422A/485. Incorrect con-
nection may result in communications errors with the host.
Connecting the Ground Wire
The PT has a functional ground terminal (FG:
1. Ground according to Figure (a) for normal grounding.
2. Do not ground the functional ground (FG:
Shorted
Open
Pin Nos. 9 and 10
• The internal circuit of the NT31/NT31C is shown below.
• For details on setting the terminal resistance of the host, refer to setting
• Connect the ground terminal (GR) of the devices to the functional ground
• Short the LG terminal of the PLC to the ground terminal (GR).
• Use a wire gauge of at least 2mm
• Refer to the manual for individual Communications Units for details on
methods for each type of the communications.
(FG:
Make sure that each signal line is grounded at only one point and ground
to 100 Ω max.
proper wiring procedures.
the same panel as devices that generate noise, such as motors or invert-
ers, as shown in Figure (b).
−
+
).
Terminal resistor (120 Ω)
Terminal resistance is applied.
Short only at the NT31/NT31C connected to the end of an RS-
422A/485 cable.
Terminal resistance is not applied.
Leave the terminals open when connecting an NT31/NT31C
anywhere other than at the end of the RS-422A/485 cable.
10 (RDB)
16 (RDA)
Abbreviation
-
-
9 (TRM)
RDB (+)
SDB (+)
TRM
FG
-
-
-
-
-
Pin number
-
Connector
hood
10
11
12
25
-
9
-
2
for the ground wire.
Making a connection here inserts
a terminator between + (RDB)
and - (RDA).
Terminal resistor setting
Function
) of the PT if it is mounted to
).
Section 5-2