Selection Of The Thermocouple; Thermocouple Type; Compensating Lead Wire; Wiring Of Thermocouple - Mitsubishi Electric FX3G User Manual

FX /FX /FX /FX /FX
3S 3G 3GC 3U
FX -4AD-TC-ADP (4-channel Thermocouple Data Input)
3U
3.4

Selection of the Thermocouple

3.4.1

Thermocouple type

• There are 2 types of thermocouples: K type and J type. When selecting the thermocouple type, make sure
that the same type of thermocouple is connection to all the channels.
• Be sure to use a non-grounded thermocouple type.
3.4.2

Compensating lead wire

To connect the thermocouple, use one of the following types of compensating lead wires:
Thermocouple
Type K
Type J
• The compensating lead wire indicates a temperature value of approximately 0.12
wire resistor (10 Ω). Use the appropriate compensating lead wire when considering this difference.
• If the compensating lead wire is very long, the wire may be easily affected by noise, etc. It is, therefore,
recommended for the length of the compensating lead wire to be 100 m or less.
3.5

Wiring of Thermocouple

Wiring depends on the thermocouple type selected. Refer to the following wiring diagrams:
3.5.1

Wiring of thermocouple type K

*1. It is not necessary to connect lines to the J-type terminals. Leave these terminals disconnected.
*2. Keep the thermocouple away from inductive noise (commercial power, etc.).
*3. For FX
3S
available.
L-16
PLC User's Manual - Analog Control Edition
3UC
KX,KCA,KCB,KCC
JX
Terminal block
OPEN
Thermocouple Compensating
*2
type K lead wire
Shield
*3
24V DC
Class-D
grounding
L+, L-, ch: represents the channel number.
/FX /FX Series PLC (AC power type), the 24 V DC service power supply is also
3G 3U
Type of compensating lead wire
TC-ADP
Type J
*1
Type J
Temperature
compensating circuit
3k
ch
L+
L-
Temperature
compensating circuit
3k
ch
L+
L-
24+
24-
3.4 Selection of the Thermocouple
°
C higher than that of the
+5V
3 Wiring