Rockwell Automation 1770-HT8 SMART TRANSMITTER - Manual (Page 29)

Installing the Smart Transmitter Interface
Products
Chapter 2
2-4
The Communications Controller can support a maximum of 32 HART
channels via the Terminal Blocks. Use any of the following combinations:
one or two 16 Channel Terminal Blocks (1770-HT16)
one, two, three or four 8 Channel Terminal Blocks (1770-HT8)
one 16 Channel Terminal Block and one or two 8 Channel Terminal
Blocks
Digital Communications Cables
The connecting cables should be shielded multi-conductor cables with 8
twisted 20-24 AWG wire pairs. These are not supplied with the Smart
Transmitter Interface. Belden #9508 (24 gauge) or # 85168 cable (20
gauge) or equivalent is recommended. Line 1 is shield, line 2 power and
lines 3 to 17 are control.
The connections between the Communications Controller and the Terminal
Blocks can be either a linear or star topography. You can use any
combination of linear/star connections as long as you adhere to the cabling
length requirements.
If your particular setup requires cable lengths greater than the ones
indicated in Figure 2.3 to Figure 2.5 or is substantially different, refer to
Appendix C.
Connecting the
Communications Controller to
the Terminal Blocks