Thermocouple Input Wiring - Siemens 353 User Manual

UM353-1B

7.4.5 Thermocouple Input Wiring

Function blocks AINU1 and AINU2 can be configured for thermocouple or RTD input.
Thermocouple input wiring is shown in Figure 7-13. Shown is a typical grounded tip thermocouple. If an
ungrounded thermocouple is used, the thermocouple wire shield can be grounded at the Siemens 353.
Thermocouple wire often has a solid conductor. Make connections as outlined in Section 7.4.1. Be sure that the
solid conductor is satisfactorily clamped by the terminal screw and pressure plate. Two reference junctions (RJ) are
supplied in the I/O Expander board installation kit. Install as outlined below.
Figure 7-13 Universal Analog Input AINU1, Thermocouple Input
Thermocouple reference junction (RJ) installation:
1. Slip a length of insulating sleeving over the portion of each reference junction lead that will remain exposed
after installation. Carefully form the leads as shown in Figure 7-14.
2. Loosen the two terminal screws using a straight blade screwdriver with a 1/8" (3 mm) blade width. Insert the
reference junction leads into the two openings in the side of the connector adjacent to the selected terminal
numbers.
Carefully press the reference junction down between the connectors, as shown below.
April 2012
Model 353
Rear Terminals
+
45
Thermocouple Wire
T/C
+
46
_
47
RJ
_
48
Notes:
1. RJ - Cold Junction Reference
2. See Table 7-1 for AINU2 terminals.
3. Grounded junction shown. For ungrounded junction, connect
cable shield to AINUc_ (Analog Input Universal Common).
0.63
(15.9)
Notes:
1. Insulate leads with sleeving.
2. Dimensions are in inches (millimeters)
and are approximate.
Figure 7-14 Reference Junction Lead Formation
Isolated
Power
Universal
Converter,
Isolated
Inputs
Isolated
Ground
MG00512a
0.06
(1.5)
0.3
(7.9)
0.5
(12.7)
0.1
(0.25)
Installation
7-15