Viconics VBZS Engineering Guide Specifications - Manual (Page 12)

Economizer Mode and CO
2
Level Control
If the fresh air damper is to be used for both free cooling and CO
2
level control (economizer mode and
CO
2
level control, but without fresh air measurement station), only the Min Pos, Max Pos, Min CO
2
and
Max CO
2
parameters as well as the free cooling sequence will be active.
- The FA Range parameter should be set to 0 CFM.
- Set AI1 parameter to CO
2
(0 VDC = 0ppm ; 10VDC = 2000ppm)
- Min Pos, Max Pos, Min CO
2
and Max CO
2
parameters should be set according to the required
setting.
The highest value between free cooling demand output and
interpolation output for the fresh air setpoint will be the output to
the fresh air damper.
Economizer Mode, CO
2
Level Control and Fresh Air Measurement Station
If the fresh air damper is to be used for both free cooling and CO
2
level control with a fresh air
measurement station, only the Min FA, Max FA, Min CO
2
and Max CO
2
parameters as well as the free
cooling sequence will be active.
- The FA Range parameter should be set to something other than 0 CFM.
- Use an air flow transmitter to read fresh air level with AI2 input (0-5 VDC input)
- Min FA, Max FA, Min CO
2
and Max CO
2
parameters should be set according to the required
setting.
The highest value between free cooling demand output and
interpolation output for the fresh air setpoint based on the CO2
level will be the output to the fresh air damper
Min Pos
Max Pos
Min CO
2
Max CO
2
Current
Fresh Air
Setpoint
Current CO
2
Level
Min FA
Setpoint
Max FA
Setpoint
Min CO
2
Max CO
2
Current
FA Setpoint
Current CO
2
Level