APPENDIX B — OPTIONAL BACNET COMMUNICATIONS WIRING (cont)
a48-8582
Fig. E — BT485 Terminator Installation
To install a BT485 terminator, push the BT485 terminator on to the BT485 connector located near the BACnet connector.
NOTE: The BT485 terminator has no polarity associated with it.
To order a BT485 terminator, consult Commercial Products
MS/TP WIRING RECOMMENDATIONS — Recommen- dations are shown in Tables C and D. The wire jacket and UL
temperature rating specifications list two acceptable alterna- tives. The Halar specification has a higher temperature rating and a tougher outer jacket than the SmokeGard specification, and it is appropriate for use in applications where the user is concerned about abrasion. The Halar jacket is also less likely to crack in extremely low temperatures.
NOTE: Use the specified type of wire and cable for maximum signal integrity.
|
| Table C — MS/TP Wiring Recommendations | |
|
|
|
|
| SPECIFICATION |
| RECOMMMENDATION |
| Cable |
| Single twisted pair, low capacitance, CL2P, 22 AWG (7x30), TC foam FEP, plenum rated cable |
| Conductor |
| 22 or 24 AWG stranded copper (tin plated) |
| Insulation |
| Foamed FEP 0.015 in. (0.381 mm) wall 0.060 in. (1.524 mm) O.D. |
| Color Code |
| Black/White |
| Twist Lay |
| 2 in. (50.8 mm) lay on pair 6 twists/foot (20 twists/meter) nominal |
| Shielding |
| Aluminum/Mylar shield with 24 AWG TC drain wire |
| Jacket |
| SmokeGard Jacket (SmokeGard PVC) 0.021 in. (0.5334 mm) wall 0.175 in. (4.445 mm) O.D. |
|
| Halar Jacket | |
|
|
| |
| DC Resistance |
| 15.2 Ohms/1000 feet (50 Ohms/km) nominal |
| Capacitance |
| 12.5 pF/ft (41 pF/meter) nominal conductor to conductor |
| Characteristic Impedance |
| 100 Ohms nominal |
| Weight |
| 12 lb/1000 feet (17.9 kg/km) |
| UL Temperature Rating |
| SmokeGard 167°F (75°C) |
|
| Halar | |
|
|
| |
| Voltage |
| 300 Vac, power limited |
| Listing |
| UL: NEC CL2P, or better |
| LEGEND |
|
|
AWG | — American Wire Gage |
|
|
CL2P | — Class 2 Plenum Cable |
|
|
DC | — Direct Current |
|
|
FEP | — Fluorinated Ethylene Polymer |
|
|
NEC | — National Electrical Code |
|
|
O.D. | — Outside Diameter |
|
|
TC | — Tinned Copper |
|
|
UL | — Underwriters Laboratories |
|
|
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