Honeywell HC900 User Manual

Page of 228
I/O Module Installation and Wiring - Module Placement in Racks 
58 
  HC900 Hybrid Controller Installation and User Guide 
Revision 5 
  
9/03 
Terminal Block Styles 
The terminal block is available in the barrier style, shown at left in 
Figure 26, and the Euro style, shown at right.  
Both styles of terminal blocks have an embossed numbering "key" 
that shows the numbering pattern of the 20 connections.   
The frame associated with the terminal block has a transparent 
hinged door.  The hinged door is a tool secured cover. To open the 
door, insert a flat screwdriver into the slot at the top and bottom of 
the door  while pulling out. The door has molded-in tabs that hold 
labels, which are uniquely color-coded to identify each module type.  
Each label is printed on both sides.  On the front (visible when the 
door is closed) are I/O channel numbers, with spaces in which 
tagnames can be written.  On the back (visible when the door is 
open) are wiring patterns for the type of module located in the slot.  
Figure 26 - Terminal Block Styles 
The 20-pin, inline connectors at the back of the terminal blocks are universal; that is, any type of I/O 
module can be used with either the Barrier style or the Euro style terminal block.   
 
 
ATTENTION 
Before mounting terminal blocks in the rack, be sure they are properly keyed to the module 
type they will be used with. See I/O Installation Procedures, page 63. 
 
Terminal Block Colors and Keying 
Both the barrier style and the Euro style are available in two colors (red and black).  Black terminal blocks, 
which have gold-colored contacts, are used for low-voltage, low-energy signals such as contact inputs and 
low DC voltages.  Red terminal blocks, which have tin-colored contacts, are used for higher voltages such 
as 120/240 Vac. 
Colors of each Terminal Blocks must correlate to that of the mating header on I/O modules with which they 
are used; that is: 
•  Black terminal blocks, which have gold-colored contacts, are for use with I/O modules that have black 
headers and gold-colored pins in the 20-pin connector; these include: Analog Input, Analog Output, 
DC Input, DC Output, and Contact Input. 
•  Red terminal blocks, which have white (tin) contacts, are for use with I/O modules that have red 
headers and white- (tin-) colored contacts in the 20-pin connector; these include: AC Input, AC 
Output, and Relay Output. 
•  Terminal blocks may be keyed by the installer to prevent high voltage terminal blocks from being 
installed on low voltage modules. See Table 14. 
Any of the color-coded labels will fit into the door of any terminal block.  Use care to ensure that all 
hardware components match each other, and also match the control strategy in the configuration file.  Use 
of documentation aids in Appendix A will facilitate correct use of labels.