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

FX /FX /FX PLC User's Manual - Analog Control Edition
3G 3U 3UC
FX -4AD-ADP (4-channel analog Input)
3U
3.4

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).
3.5

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.
C-14
If current input is selected:
*1
If voltage input is selected:
*1
Connection of external
power supply line
24V DC
Class-D
grounding
V +, 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
4AD-ADP
Terminal
block
V +
250Ω
*2
I +
47kΩ
COM
147kΩ
V +
250Ω
I +
47kΩ
COM
24+
24-
Other
PLC
equipment
Common grounding
Not allowed
2
3.4 Analog Input Line
147kΩ
ch
ch
+15V
).
3 Wiring