D-12
3 Wiring
3.3 Analog Input Line
FX
3G
/FX
3U
/FX
3UC
PLC User's Manual - Analog Control Edition
FX3G-2AD-BD (2-channel analog Input)
3.3 Analog Input Line
For analog input, "voltage input" or "current input" can be selected for each channel.
*1. Use the 2-core shielded twisted pair cable for the analog input lines, and separate the analog input
lines from other power lines or inductive lines.
*2. If "current input" is selected, be sure to short the line between the V+ terminal and the I+ terminal.
(: Channel number).
*3. Make sure to short-circuit the "V+" and "VI-" terminals when ch is not used.
3.4 Grounding
Grounding should be performed as stated below.
• The grounding resistance should be 100Ω or less.
• Independent grounding should be performed for best results.
When independent grounding is not performed, perform "shared grounding" as shown in the following
figure.
→ For details, refer to the User’s Manual - Hardware Edition of the PLC Series.
• The grounding wire size should be AWG22 to 20 (0.3 to 0.5 mm
2
).
• The grounding point should be close to the PLC, and all grounding wires should be as short as possible.
If current input selected:
2AD-BD
V +, I +, ch :
250Ω
250Ω
88.7kΩ
88.7kΩ
110kΩ
110kΩ
ch
I +
I +
V +
V +
VI-
ch
Class-D
grounding
Terminal
block
Class-D
grounding
*2
*3
*1
*1
If voltage input is selected:
represents the channel number.
PLC
Other
equipment
PLC
Other
equipment
PLC
Other
equipment
Shared grounding
Good condition
Common grounding
Not allowed
Independent grounding
Best condition
