Trane Tracer SC (Standalone Controller) and SC+ (Enhanced) are powerful field controllers used in commercial HVAC systems. While Trane typically integrates through proprietary systems, Tracer SC/SC+ also function as native BACnet servers, allowing integration with third-party BAS platforms like Niagara, Desigo, and others.
| Feature | Tracer SC | Tracer SC+ | Tracer SC Plus |
|---|---|---|---|
| Firmware | v7.x+ | v8.x+ | v9.x+ |
| Max I/O | 32 points | 64 points | 128 points |
| Typical Use | Single RTU, small AHU | Multi-zone AHU, plant | Campus, large plant |
| BACnet Support | Server only | Server + Client | Full BACnet/IP + MSTP |
| MSTP Trunks | 1 | 2 | 4 |
| Point Name | Object Type | Units | Writable | Notes |
|---|---|---|---|---|
| Room Temperature | Analog Input | degF | No | Zone sensor reading |
| Duct Static Pressure | Analog Input | inWC | No | Duct sensor |
| Zone Demand | Analog Input | % | No | Calculated by controller |
| Outdoor Air Temp | Analog Input | degF | No | From outdoor sensor |
| Supply Air Temp | Analog Input | degF | No | Discharge sensor |
| Damper Position Cmd | Analog Output | % | Yes | 0-100% open |
| Heating Setpoint | Analog Output | degF | Yes | Occupied heating SP |
| Cooling Setpoint | Analog Output | degF | Yes | Occupied cooling SP |
| Occupied Status | Binary Input | on/off | No | Schedule or sensor |
| Fault Indicator | Binary Input | fault/ok | No | Controller self-diagnostic |
| Fire Alarm | Binary Input | alarm/ok | No | From fire panel input |
| VAV Damper Enable | Binary Output | on/off | Yes | Enable/disable damper |
| Reheat Valve Enable | Binary Output | on/off | Yes | Enable reheat coil |
| Point Name | Object Type | Units | Writable |
|---|---|---|---|
| Return Air Temp | Analog Input | degF | No |
| Supply Air Temp | Analog Input | degF | No |
| Suction Pressure | Analog Input | psig | No |
| Discharge Pressure | Analog Input | psig | No |
| Entering Water Temp | Analog Input | degF | No |
| Leaving Water Temp | Analog Input | degF | No |
| Mixed Air Damper Cmd | Analog Output | % | Yes |
| Cooling Capacity Cmd | Analog Output | % | Yes |
| Reheat Valve Cmd | Analog Output | % | Yes |
| Unit Enable | Binary Output | on/off | Yes |
| Compressor 1 Status | Binary Input | on/off | No |
| Compressor 2 Status | Binary Input | on/off | No |
| Supply Fan Status | Binary Input | on/off | No |
| Filter Alarm | Binary Input | alarm/ok | No |
// Read room temperature from Tracer
BACnetAnalogInput[DeviceID=1400100, ObjectID=AI:1] -> RoomTemp_Display
// Write setpoint to Tracer
HeatingSetpoint_Slider -> BACnetAnalogOutput[DeviceID=1400100, ObjectID=AO:2]
// Alarm binding
IF BACnetBinaryInput[DeviceID=1400100, ObjectID=BI:2] == FAULT THEN
Trigger NiagaraAlarm(Priority=HIGH, Message="Tracer SC Fault Detected")
Symptoms: Intermittent point failures, stale values, timeout errors in BAS log.
Root Causes: Network congestion, firewall blocking port 47808, Tracer CPU overloaded, APDU timeout too short.
Solutions:
Symptoms: Device discovered but specific objects return Access Denied error.
Solutions:
Trane VAV controllers (Voyager series) connect to Tracer SC via RS-485 MSTP trunk.
| Parameter | Recommended Value |
|---|---|
| Baud Rate | 38400 (match all devices) |
| Max Master | Number of devices + 1 |
| Max Info Frames | 5 |
| MSTP Address Range | 1-127 (each device unique) |
| Cable | Shielded twisted pair, daisy-chain |
| Max Length | 1200m (4000ft) at 38400 baud |
| Termination | 120 ohm resistor at each end |
| Model | Minimum for BACnet | Recommended | Notes |
|---|---|---|---|
| Tracer SC | v7.2 | v7.5+ | Basic BACnet server |
| Tracer SC+ | v8.1 | v8.4+ | Full BACnet/IP + MSTP |
| Tracer SC Plus | v9.0 | v9.2+ | Enhanced object model |
Warning: Firmware update causes brief network outage. Schedule during unoccupied hours.
No additional license required for third-party BACnet integration. The BACnet server is a built-in feature of Tracer SC/SC+ firmware. Trane Client software license only needed for direct USB/serial configuration.