QCS-336 System Controller

COSYS Building Controls



Our COSYS Application and System Controls work along with our enterprise software platform OspreyFMS to provide a meaningful context.

The QCS-336 is a fully programmable, Native BACnet® Building Controller that communicates on Twisted-Pair Ethernet 10-BaseT using BACnet IP and BACnet over Ethernet, or on an RS-485 LAN using the BACnet MS/TP protocol. The QCS-336 is designed for a wide-range of applications that have small local I/O requirements. It also supports BACstat® and other LINKnet devices.


  • Fully programmable
  • BACnet IP and BACnet over Ethernet communications
  • Super capacitor for real-time clock and SRAM backup (requires no maintenance)
  • Supports 12 BACstat network sensors on LINKnet for room sensing
  • Actuator power terminal (24 VAC) for each analog output (can be powered internally or from an auxillary transformer)
  • Firmware upgrade and database load/save over the network
  • Optional field upgrade to Modbus® RTU with hardware key
  • Service port
  • Screw or DIN rail mountable
  • LED indicator for output, power, CPU and SCAN status


The QCS-336 is suitable for controlling various packaged units and equipment with small I/O requirements such as fan coil units, unit ventilators, heat pumps, and small boilers or chillers.

The fully programmable QCS-336 can be tailored to specific applications by creating and modifying BACnet objects and GCL+ programs.


BACnet Device Profile
BACnet Building Controller (B-BC)

6 Universal Inputs (10-bit) supporting:
0-5 VDC
0-10 VDC
10 kΩ Thermistor
Dry Contact (using 10 kΩ Thermistor jumper setting)
4-20 mA

3 Binary TRIAC Outputs

Switching 24 VAC @ 0.5 A max per output
100 µA leakage current per TRIAC, 25 mA min current

3  Analog Outputs

0-10 VDC @ 20 mA max output Software configurable as binary or analog

Device Addressing
Set via DIP switches and jumpers, or software setup

Removable screw-type terminal connectors

Wiring Class
Class 2 / SELV

24 VAC @ 12 VA, 48 VA with binary TRIAC outputs fully-loaded

16-bit processor
2 MB (16 megabit) Flash memory
319 KB SRAM memory for database Real-time clock
Super capacitor for 72-hr backup of real-time clock and SRAM

Communications Ports
Ethernet (10-BaseT)
BACnet IP, BACnet over Ethernet
2 RS-485 NET1, NET2 supporting:

BACnet MS/TP up to 76800 bps, max 99  devices per port
LINKnet up to 76800 bps, max 12 devices on LINKnet with no more than 2  DFM devices (1 port only)
Optional Modbus up to 68400 bps, max 5 devices (1 port only)

Serial RS-232
BACnet PTP, up to 38400 bps

32° to 131°F (0° to 55°C)
10 to 90% RH (non-condensing)

8½ x 4¼ x 115/16 in. (21.8 x 10.7 x 4.9 cm) with housing

0.80 lbs. (360 g) with housing



Order the QCS-336 with the desired options according to the following product numbers:

QCS-336 System Controller 6 universal inputs, 3 analog outputs, 3 binary TRIAC outputs