Facility Environment Controller 2450

Environment Controller 2450

Sierra Monitor’s Facility Environment Controller 2450 is an electronic, microprocessor-based system designed to manage the heating, ventilating and air conditioning (HVAC) controls, environmental alarms, and manage rigorous personnel safety requirements of controlled environment vaults (CEVs) and walk-in cabinets. Recognized as the standard of the industry, the Model 2450 has been installed in over 90% of all new CEVs deployed since its introduction.

The Model 2450 employs lead/lag and demand logic to control two air conditioners. Application specific software is used to collect data from various sensor inputs to make continuous, real-time control logic and alarm decisions. The results of the logic are used to operate control outputs, send alarms to telephone company systems, and display status and alarm conditions on the front panel of the controller.

The Model 2450 also monitors CEVs for the presence of combustible and toxic gases and automatically initiates ventilation when an alarm threshold is exceeded. Alarm thresholds are automatically reduced from unoccupied levels to OSHA defined, occupied levels to further ensure personnel safety.


120 VAC, 50/60/Hz

-48 VDC (20-66 VDC)

5 Watts nominal


Motorola 68HC11 with watchdog timer

Clock Speed 8 MHz

2.5 Kbytes EEPROM

64K bytes EPROM

Real Time Clock w/ 30 day backup by a

super capacitor


Hayes Compatible 2400 Baud


Supports any terminal communication program via modem or direct serial connection. Over 70 programmable set points and two level access code


Operating Range: 4o to 122oF (-20o to 50oC)

Storage Range: -40o to 122oF (-40o to 50oC)


0 – 95% RH

Front Panel

Vacuum fluorescent alphanumeric (2 rows x 20 characters)


4 LED’s for run modes

10 LED’s for alarm status

14 LED’s for control status


6 keys for run modes (4) and reset (2)

Malfunction Protection

Automatically turns on blower, air damper, red indicator and malfunction alarm if system malfunctions


Serial: Serial port for direct connection to portable PC or hand held terminal for viewing data or changing set points

Front Panel: Keypad selection of operating modes: Run, View, Test, Calibrate, Sensor Mapping

Sensor Range
Temperature 0 o to 221oF (-15o to 105oC)
Humidity 0-100% Relative Humidity
Combustible Gas 5,000 ppm (10% LEL)
Oxygen 25% by volume
Hydrogen Sulfide 100 ppm

NEMA 1 with hinged sensor cover panel


Mounts on door of control panel


8.75 x 11.25 x 2 in. (22.2 x 28.6 x 5.1 cm)


3.2 lb. (1.9 Kg)

Inputs (Total Digital Inputs:17, Total Analog Inputs: 6)



Gas Sensors (4)

External (Terminals on 2490, controls in 2450)


  • Intrusion
  • Door Open
  • AC Failure
  • Smoke Alarm
  • Duct Sail Switch
  • High Water Alarm
  • Pump On Level Switch
  • Pump Off Level Switch
  • Spares (Qty. 9)
  • Analog (Optional sensors available)
  • External Temperature
  • Internal Temperature #1
  • Internal Temperature #2
  • External Relative Humidity
  • 0-10 VDC Spare
  • 4-20 mA DC Spare
Outputs (Total Control Relays: 14, Total Alarm Relays: 17)
Controls (Terminals on 2490, controls and relays in 2450)

SPST (Form A), 0.5 Amp, 60 VDC or 30 VRMS (AC),

Normally open contacts

Air Conditioner #1

Air Conditioner #2

Air Damper

Blower #1

Blower #2

Condenser #1

Condenser #2



Sump Pump

Emergency Lights

Green Indicator

Red Indicator

Alarms (Relays on 2490 or in separate 2495 Alarm Connection Module, controls in 2450)

SPST (Form A), 0.5 Amp, 60 VDC, 30 VRMS (AC)

Pump Run

High Water

High Humidity

High Temperature

Vent Sail


Combustible Gas

Carbon Monoxide


Hydrogen Sulfide

AC Power Fail



Gas Detection Trouble

Common Motor

Current Alarm Spare (2)

Application Specific Software

Execute full HVAC control of structures for a precisely controlled and safe environment for telecom equipment and personnel

Environmental Control with integral Gas Detection

Monitor hazardous gas and environments and control HVAC units with lead/lag and demand logic

Operator Friendly Control Panel

Easily operate controls through a fluorescent front panel keypad and display

Convenient Computer Interface

Integral data port and modem allow bi-directional communication to hand held devices or remote computers for diagnostics, set point management and reporting.

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