Input Calibration 
284  UDC3500 Universal Digital Controller Product Manual  3/07 
 
5.4.3 RTD Inputs 
Refer to Figure 5-4 and wire the controller according to the procedure given in Table 5-5.  
Table 5-5  Set Up Wiring Procedure for RTD Inputs 
Step  Action 
1 
Connect the copper wires to the terminals for the input to be calibrated. See Figure 
5-4. 
 
 
Decade
 
Resistance
 
Box
 
Copper Leads
 
Equal Length
 
30-
29+
31R
32+
33-
34R
35+
36-
28R
Input 1 
Input 2 
Input 3 
 
Figure 5-4  Wiring Connections for RTD (Resistance Thermometer Device) 
 
ATTENTION 
Decade Resistance Boxes are usually not accurate enough to meet the 0.02% accuracy 
requirement noted in Table 5-2. This can be overcome by performing a four-wire resistance 
measurement with a precision DMM and then adjusting the Decade Box to the correct zero and 
span resistance values as given in 
Table 5-1. Determine the proper zero and span resistance 
settings prior to attaching the Decade Box to the instrument. For best accuracy, measure with 
the DMM connected to the wire ends rather than directly to the Decade Box.