L-15
3 Wiring
3.6 Caution Regarding Wiring
FX
3G
/FX
3U
/FX
3UC
PLC User's Manual - Analog Control Edition
FX3U-4AD-TC-ADP (4-channel Thermocouple Data Input)
K
FX
3U
-4AD-PNK
-ADP
L
FX
3U
-4AD-TC
-ADP
M
PID Instruction
(FNC 88)
3.5.2 Wiring of the thermocouple type J
*1. To use a J thermocouple type, be sure to connect the thermocouple to these terminals. In addition,
select J type by turning on the type K/J selection special auxiliary relay.
*2. Keep the thermocouple away from inductive noise (commercial power, etc.).
3.6 Caution Regarding Wiring
• It is not possible to connect different types of thermocouples to 4 channels of TC-ADP. Be sure to use the
same type of thermocouple for all the channels.
• TC-ADP is not insulated between the channels. For this reason, be sure to use a non-grounded type
thermocouple.
• Be sure not to connect to the terminal "•".
3.7 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.
3k
Ω
ch
TC-ADP
Class-D
grounding
+5V
L
+
L
-
24+
24-
Terminal block
24V DC
L
+, L
-, ch
:
represents the channel number.
type J
Thermocouple
type J
*2
ch
L
+
L
-
3k
Ω
Shield
*1
Compensating
lead wire
Temperature
compensating circuit
Temperature
compensating circuit
type J
PLC
Other
equipment
PLC
Other
equipment
PLC
Other
equipment
Shared grounding
Good condition
Common grounding
Not allowed
Independent grounding
Best condition
