Technical data
Publication 1794-2.1 - January 2000
130 24V dc Thermocouple/mV Input Module Cat. No. 1794-IT8 FLEX I/O and FLEX Integra Product Data
Data Type
mV Mode
Channel
1794-TB3, -TB3S, -TB2 Terminal Base Unit
High Signal Term.
(+)
Low Signal Term.
(-)
Shield
Return
Not
Used
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 16 thru 33
+24V dc power 34 thru 51 (34 and 51 for TB2)
Thermo-cou
ple
Channel
1794-TB3T, -TB3TS Terminal Base Unit
High Signal Term.
(+)
Low Signal Term.
(-)
Not
Used
Shield
Return
0 A-0 A-1 B-17 B-39
1 A-2 A-3 B-19 B-40
2 A-4 A-5 B-21 B-41
3 A-6 A-7 B-23 B-42
4 A-8 A-9 B-25 B-43
5 A-10 A-11 B-27 B-44
6 A-12 A-13 B-29 B-45
7 A-14 A-15 B-31 B-46
24V dc Common 16, 17, 19, 21, 23, 25, 27, 29, 31 and 33
+24V dc power 34, 35, 50 and 51
0123456 78 9101112131415
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
33
16
34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49
51
50
1794-TB3, -TB3S, -TB2, -TB3T, or -TB3TS
0 1234567891011
12
13 14
15
0-15
16-33
34-51
A
B
C
Word Description
Write
Word
0
Module Data Type
Bit 01 00 Definition
00
o
C (default)
1
01
o
F
1 0 Bipolar counts scaled between -32768 and +32767
(default)
1 1 Unipolar counts scaled between 0 and 65535
1 For millivolts there are two implied decimals. For degrees and ohms there is one
implied decimal.
CJC CJC
-
+
0-15
16-33
34-51
A
B
C
Channel 0 (Terminals 0 and 1 with shield to 39)
30236
Example of Thermocouple Wiring to 1794-TB3T Base Unit
0 12345
678
91011
12
13 14
15
ch 0-3 ch 4-7
CJC = cold junction
compensation kit
1794-CJC2/A (kit supplied
with module and contains 2
compensators)
This is a non-isolated module. You may need to take extra precautions when using
grounded thermocouples, like tying the 24V dc common to the earth ground.
-
+
0-15
16-33
34-51
A
B
C
Channel 0 (Terminals 0, 1 and 17)
30237
Example of mV Input Wiring to 1794-TB3 or -TB3S Base Unit
012345
678
91011
12
13 14
15
mV
Source
mV input
Channel 1