Installation 
3/07  UDC3500 Universal Digital Controller Product Manual  23 
Digital equipment is especially sensitive to the effects of electrical noise. Your controller 
has built-in circuits to reduce the effect of electrical noise from various sources. If there 
is a need to further reduce these effects: 
•  Separate External Wiring—Separate connecting wires into bundles 
(See Permissible Wiring Bundling - Table 2-5) and route the individual bundles 
through separate conduit metal trays.  
Use Suppression Devices—For additional noise protection, you may want to add 
suppression devices at the external source. Appropriate suppression devices are 
commercially available. 
ATTENTION 
For additional noise information, refer to document number 51-52-05-01, How to Apply Digital 
Instrumentation in Severe Electrical Noise Environments. 
Permissible Wiring Bundling 
Table 2-5  Permissible Wiring Bundling 
Bundle No.  Wire Functions 
1 
•  Line power wiring 
•  Earth ground wiring 
•  Line voltage control relay output wiring 
•  Line voltage alarm wiring 
2 Analog signal wire, such as: 
•  Input signal wire (thermocouple, 4 to 20 mA, etc.) 
•  4-20 mA output signal wiring 
Digital input signals 
3 
•  Low voltage alarm relay output wiring 
•  Low voltage wiring to solid state type control circuits 
•  Low voltage wiring to open collector type control circuits