Wiring connections for the thermocouple/rtd module – Rockwell Automation 1794-IT8_IR8 FLEX I/O 8 Thermocouple Input Module User Manual
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Publication 1794-IN021D-EN-P - August 2003
7. If daisychaining power to the next terminal base, connect a jumper
from terminal 51 (+V dc) on this base unit to the +V terminal on the
next base unit.
8. If continuing dc common to the next base unit, connect a jumper
from terminal 33 (common) on this base unit to the COM (return)
terminal on the next base unit.
Wiring Connections for the Thermocouple/RTD Module
Example of 2, 3 and 4-wire RTD Wiring to a 1794-TB3
Terminal Base Unit
Example of 2, 3 and 4-wire RTD Wiring to a 1794-TB3T
Terminal Base Unit
Example of Thermocouple Wiring to a 1794-TB3T
Terminal Base Unit
Example of Grounded Thermocouple Wiring to a
1794-TB3T Terminal Base Unit
Example of Millivolt Wiring to a 1794-TB3, -TB3S or
-TB3T Terminal
Base Unit
RTD or mV
Channel
1794-TB2, -TB3 and -TB3S Terminal Base Units
High
Signal
Terminal
(H) or (+)
Low
Signal
Terminal
(L) or (-)
Signal
Return
1
(-IR8
only)
Shield
Return
0
A-0
A-1
B-17
B-18
1
A-2
A-3
B-19
B-20
2
A-4
A-5
B-21
B-22
3
A-6
A-7
B-23
B-24
4
A-8
A-9
B-25
B-26
5
A-10
A-11
B-27
B-28
6
A-12
A-13
B-29
B-30
7
A-14
A-15
B-31
B-32
24V dc Common
B-16 thru 33
+24V dc Power
-TB3, -TB3S (C-34 thru C-51); -TB2 (C-34 & C-51)
1 When using a 2-wire RTD, jumper the signal return to the low signal
terminal.
RTD, mV or
Thermocouple
1
Channel
1794-TB3T and -TB3TS Terminal Base Units
High Signal
Terminal
(H) or (+)
Low Signal
Terminal
(L) or (-)
Signal
Return
(-IR8 only)
Shield
Return
2
0
A-0
A-1
B-17
C-39
1
A-2
A-3
B-19
C-40
2
A-4
A-5
B-21
C-41
3
A-6
A-7
B-23
C-42
4
A-8
A-9
B-25
C-43
5
A-10
A-11
B-27
C-44
6
A-12
A-13
B-29
C-45
7
A-14
A-15
B-31
C-46
1
Terminals 36, 37 and 38 and 47, 48 and 49 are for cold junction compensation only,
(with 38 and 47 chassis GND).
2
Terminals 39 to 46 are chassis ground.
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15
0
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
34
1794-TB2, TB3, -TB3T
0-15
34-51
16-33
A
B
C
Shaded terminals not included on 1794-TB2 terminal base unit.
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
1 2
3 4 5 6 7 8 9 10 11 12 13 14 15
0
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
34
1794-TB3
0 -15
34-51
16-33
4-Wire RTD
2-Wire RTD
3-Wire RTD
Clip or tieback
4th lead.
Attention: Keep exposed area of inner conductor as short as possible.
A
B
C
When using a 2-wire RTD, jumper the signal return to the low signal terminal.
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
1 2
3 4 5 6 7
8 9 10 11 12 13 14 15
0
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
34
1794-TB3T
0 -15
34-51
16-33
A
B
C
Clip or tieback
4th lead.
Attention: Keep exposed area of inner conductor as short as possible.
4-Wire RTD
2-Wire RTD
3-Wire RTD
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15
0
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
34
1794-TB3T
0 -15
34 - 51
16 - 33
+
_
CJC
CJC
CJC kit Cat. No.
1794-CJC2/A
(contains 2 CJCs)
Channel 0 (Terminals 0 and 1 with shield to 39)
A
B
C
Ch. 4-7
Ch 0-3
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15
0
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
34
1794-TB3T
0 -15
34 - 51
16 - 33
+
Channel 0
(Terminals 0 and 1
with shield to 39)
CJC
CJC
CJC kit Cat. No.
1794-CJC2/A
(contains 2 CJCs)
When using grounded thermocouples, and the error is off the same
amount on each thermocouple, connect terminal 16 to ground, and
connect the thermocouple ground to the same ground,
A
B
C
_
Ch. 4-7
Ch 0-3
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15
0
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
34
1794-TB3 shown
0 –15
34–51
16–33
+
–
Millivolt input
Channel 1
Millivolt
Source
Channel 0 (T erminals 0, 1 and 17)
For more accurate readings, use the 1794-TB3T for mV measurement.