DeviceNet Base RTD and Thermocouple CompactBlock LDX I/O 9
Publication 1790-IN011C-EN-P - January 2015
1790D-T4T0 Thermocouple Input Module Terminal Block Wiring
•
Wire pin 1 to Field Power (+) 24V DC
•
Wire pin 2 to Field Power (-) GND
Connect Field Wiring
System Wiring Guidelines
Follow these guidelines when wiring your system:
•
use shielded, twisted pair wire to ensure proper operation and high immunity to
electrical noise
•
to limit noise, locate RTD and resistance device signal wires as far away as possible
from power lines, load lines and other sources of electrical noise, such as
hard-contact switches, relays and AC motor drives
•
under normal conditions, the drain wire and shield junction should be connected
to earth ground, via a panel or DIN rail mounting screw at the block end
•
keep shield connection to ground as short as possible
•
to ensure optimum accuracy, limit overall cable impedance by keeping the cable as
short as possible. Locate the I/O system as close to your field devices as your
application will permit.
RTD Wiring Guidelines
Since the operating principle of the RTD module is based on the measurement of
resistance, give special consideration when selecting the input cable. For 2-wire or 3-wire
configurations, select a cable that has consistent impedance throughout its entire length.
20
18
16
14
12
10
8
6
4
2
19
17
15
13
11
9
7
5
3
1
NC
NC
CH3_B
NC
CH0_B
NC
NC
CH2_B
CH1_B
GND
NC
NC
CH2_A
CH1_A
+24V
NC
NC
CH3_A
NC
CH0_A
