I/O Module Installation and Wiring - I/O Terminal Block Wiring Diagrams 
82   HC900 Process Controller Installation and User Guide  Revision 19 
    06/14 
I/O Terminal Block Wiring Diagrams 
Universal Analog Input Module Wiring 
The Universal Analog Input Module has eight inputs, which can include any combination of the following 
input types: RTD, TC, Ohms, Millivolt, Volt, or Milliamp. Figure 39 shows wiring examples of each of the 
analog input types. An example of wiring for eight TC inputs is given in Figure 41. 
Specifications for this module and for other modules are given in the Specifications section of this manual. 
 
 
ATTENTION 
To indicate sensor failure the Analog Input software will output a warning if 
thermocouple resistance > 80 ohms. Use appropriate gauge wiring to prevent 
inaccurate failure warnings.  
 
Table 15 – Typical Thermocouple resistance in Ohms per Double Foot @ 68 degrees F 
AWG No.  Diameter 
inches 
Type K   Type J   Type T  Type E   Type S  
Pt/ PT110 
Type R  
Pt/ PT113 
Type W5/ 
W26 
Type  W/ 
W26 
10  0.102  0.058  0.034  0.029  0.069  0.018  0.018  0.023  0.020 
12  0.081  0.091  0.054  0.046  0.109  0.028  0.029  0.037  0.031 
14  0.064  0.146  0.087  0.074  0.175  0.045  0.047  0.058  0.049 
16  0.051  0.230  0.137  0.117  0.276  0.071  0.073  0.092  0.078 
18  0.040  0.374  0.222  0.190  0.448  0.116  0.119  0.148  0.126 
20  0.032  0.586  0.357  0.298  0.707  0.185  0.190  0.235  0.200 
24  0.0201  1.490  0.878  0.7526  1.78  0.464  0.478  0.594  0.560 
26  0.0159  2.381  1.405  1.204  2.836  0.740  0.760  0.945  0.803 
30  0.0100  5.984  3.551  3.043  7.169  1.85  1.91  2.38  2.03 
Table values are shown as a reference only; actual values may vary. Consult manufacturer specifications. 
 
Isolation 
This module has eight inputs, which are isolated except for RTD current sources.  
RTD Inputs 
RTD inputs share current sources (two RTD inputs per 
source), as shown in Figure 38, Figure 39, and Figure 
40. 
For example, the current source for the RTD input at 
channel one (terminals 1 and 2) is terminal 3 (I
RTD 
1 & 
2).  This same current source (I
RTD 
1 & 2) is also used 
for an RTD input at channel two (terminals 4 and 5).   
Figure 38 and Figure 42 show examples of RTD input 
wiring (2-wire and 3-wire RTDs).  Four-wire RTD 
inputs are not available. 
Figure 38 – RTD Inputs