Grounding; Analog Input Line - Mitsubishi FX3U-4AD User Manual

FX /FX /FX PLC User's Manual - Analog Control Edition
3G 3U 3UC
FX -2AD-BD (2-channel analog Input)
3G
3.3

Analog Input Line

For analog input, "voltage input" or "current input" can be selected for each channel.
If current input selected:
If voltage input is selected:
V
*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.
PLC
equipment
Independent grounding
Best condition
• The grounding wire size should be AWG22 to 20 (0.3 to 0.5 mm
• The grounding point should be close to the PLC, and all grounding wires should be as short as possible.
D-12
Terminal
block
*1
*2
Class-D
grounding
*1
Class-D
grounding
+, I +, ch : represents the channel number.
→ For details, refer to the User's Manual - Hardware Edition of the PLC Series.
Other Other
PLC
equipment
Shared grounding
Good condition
2AD-BD
110kΩ
V +
250Ω
I +
88.7kΩ
110kΩ
V +
250Ω
I +
88.7kΩ
VI-
*3
Other
PLC
equipment
Common grounding
Not allowed
2
).
3 Wiring
3.3 Analog Input Line
ch
ch