Selection Of The Platinum Resistance Thermometer Sensor - Mitsubishi FX3U-4AD User Manual

FX /FX /FX PLC User's Manual - Analog Control Edition
3G 3U 3UC
FX -4AD-PT-ADP (4-channel Platinum Resistance Thermometer Data Input)
3U
3.4

Selection of the Platinum Resistance Thermometer Sensor

Select the Pt100 3-wire platinum resistance thermometer sensor.
This thermometer will not be affected by voltage drop in the wiring area, and will ensure accurate
measurement.
3.5 Wiring of the Platinum Resistance Thermometer Sensor
Pt100
Pt100
L +, L -, I -, ch :
*1. Separate the cable of the platinum resistance thermometer sensor from the other power cables or
areas easily affected by inductive noise (of the commercial power, etc.).
3.6 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.
H-14
Twisted shielded
Terminal
cable *1
Shield
Twisted shielded
*1
cable
24V DC
Class-D grounding
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
3.4 Selection of the Platinum Resistance Thermometer Sensor
PT-ADP
+5V
4.7kΩ 4.7kΩ
block
100kΩ
L +
L -
100kΩ
I -
+5V
4.7kΩ 4.7kΩ
100kΩ
L +
L -
100kΩ
I -
24+
24-
Other
PLC
equipment
Common grounding
Not allowed
2
ch
ch
+5V
).
3 Wiring