CBT 4T4 2U1R

BACnet® Advanced Application Controller

The CBT-4T4-2U1R is a freely programmable BACnet controller with native MS/TP communications support. The controller is BTL listed as a BACnet Advanced Application Controller (B-AAC) and is ideally suited for the control of Fan Coil Units with ECM, Heat Pumps, Unit Ventilators, Unit Heaters, Chilled Ceilings/Beams and custom unitary equipment.

Part of Cylon’s CB Line of BACnet field controllers, the CBT-4T4-2U1R features 4 Uniputs™ with Triac (configurable as inputs OR outputs), 4 Universal Inputs, 2 UniPuts, 1 Digital Output with a high-power relay output and a dedicated input for Cylon’s CBT-STAT intelligent room sensors.


CBT-4T4-2U1R is suitable for controlling a variety of small to medium-sized HVAC equipment such as:

  • Fan Coil Units with ECM
  • Heat Pumps
  • Unit Ventilators
  • Chilled Ceilings/Beams
  • Unit Heaters
  • Exhaust Fans
  • Custom Unitary Equipment


  • BACnet MS/TP Fieldbus Supports the following configurable BACnet objects: AI/BI/AO/BO/AV/BV, Trend Logs, and Schedules
  • 4 Uniputs™ with Triac Configured as analog / digital outputs or voltage inputs along with Triac functionality that can switch a 24 V AC load.
  • 4 Universal Inputs can be configured as analog or digital inputs 
  • 2 UniPuts™ can be configured as analog / digital outputs or voltage inputs. 
  • 1 Mains Relay
  • Up to 500 Strategy Blocks
  • Up to 6 Trendlogs  
  • 1024 entries per Trendlog  
  • Data Security Strategy and setpoints backed up in Flash 


Processor  STM32F103ZET6 32bit processor
Clock Speed 8 Mhz Crystal, 72 Mhz internal processor clock rate
System Memory (soldered to PCB not removable) Internal Flash 512 Kbyte, Internal SRAM 64 Kbyte, External Flash 16 Mbyte, External SRAM 1 Mbyte
Supply Requirements 24 VAC +15%/-20% 50/60 Hz
Transformer Rating 12 VA typical, 81 VA max with all external loads
Relay Rating 250 V AC@ 8 A
BACnet Loading 1/4 unit load device
Terminals PCB mounted plug terminal connections
Conductor Area Max: AWG 12 (3.09 mm2) Min: AWG 22 (0.355 mm2)
Temperature & Humidity 32° to 122° F (0° to 50° C) ambient 0-90% RH non-condensing
Storage Temperature -22° to 158° F (-30° to +70° C)
EMC Immunity / Emission EN 55024,2010 / EN55022, 2010 Class A
Approvals BTL Listed - BACnet Advanced Application Controller (B-AAC) UL Listed (CDN & US)
UL 916 Energy Management Equipment
File Number E176435
Safety EN 60730-1:2011
Automatic Action type i.e. Type 1.B.Y.
Pollution Degree Class 2 (EN 607301-1)
Additional Info
Size 5.1" x 5.1" x 1.7" (145 x 130 x 45 mm)
Enclosure Injection-molded ABS
Mounting (DIN rail)
(724) 733-2000
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