Orion System System Manager TS II In-House - Manual (Page 35)

SMTS II Technical Guide
VCM & VCM-X Controllers
35
VCM & VCM-X Static Setpoints
Static Setpoints
Touch the < Static> button to access the Static Setpoint
Screens.
Duct Static Setpoint
For VAV units, a Supply Fan VFD or Bypass Damper Actuator is used to
maintain the Duct Static Pressure Setpoint. The Static Pressure Output
Signal varies to control the Static Pressure Setpoint. The Duct Static
Pressure is maintained at this setpoint while the Main Fan is running.
High limit = 3.00”WG; Low limit = 0.10”WG; Default = 0.50”WG.
Static Setpoint Deadband
The Duct Static Setpoint accuracy is controlled by this value. No Main
Fan VFD changes are made if the static is within this range of this set-
point. High limit = 1.00”WG; Low limit = 0.01”WG; Default = 0.10”WG.
Static Control Interval
The Duct Static Control output is adjusted at a rate equal to this value. If
the Duct Static Pressure is above the Static Setpoint plus the Deadband,
the Static Pressure Output Signal will be reduced at every Control Rate
interval. If the Static Pressure is below the Static Setpoint minus the
Deadband, the Output signal will be increased at every Control Rate
interval. High limit = 30 seconds; Low limit = 1 second; Default = 10
seconds.
Building Pressure Setpoint
The Building Pressure is maintained at this setpoint while the Main
Fan is running. See detailed explanation in next column. High limit =
0.20”WG; Low limit = -0.20”WG; Default = 0.10”WG.
Building Setpoint Deadband
The Building Pressure Setpoint accuracy is controlled by this value. No
Relief Fan VFD changes are made if the pressure is within this range
of this setpoint. See detailed explanation in next column. High limit =
0.10”WG; Low limit = 0.01”WG; Default = 0.02”WG.
Building Pressure Setpoint and Deadband
Direct Acting Control:
If an Exhaust Fan Relay is confi gured, when the Building Static Pres-
sure rises above the Building Pressure Setpoint plus the Deadband, the
Exhaust Fan Relay will activate. It will remain on until the Building
Pressure falls below the Building Pressure Setpoint minus the Deadband.
If Modulating Building Pressure is confi gured, when the Building Static
Pressure rises
Static
above the Building Pressure Setpoint plus the Deadband, the Building
Pressure Output Signal will increase until the Building Static Pressure
falls within the Deadband. If the Building Static Pressure falls below the
Building Pressure Setpoint minus the Deadband, the Building Pressure
Output Signal will decrease until the Building Static Pressure rises within
the Deadband. The Building Pressure Output Signal is confi gurable for
0-10 or 2-10 VDC. For more detailed operation information, see the
VCM-X Controller Technical Guide for the complete Building Pressure
Control Sequence of Operation.
Reverse Acting Control:
The Building Pressure Output Signal remains a Direct Acting 0-10 or
2-10 VDC signal, but the logic is reversed. On a drop in Building Static
Pressure below the Building Pressure Setpoint minus the Deadband,
the Building Pressure Output Signal will increase to modulate open the
Outdoor Air Damper. When this option is used, no economizer or IAQ
operation will be available.
Economizer Minimum Position
The Economizer (Outdoor Air Damper) Min Position Setpoint is main-
tained during the Occupied Mode even if the Economizer is disabled
due to the Outdoor Air Temperature or Wetbulb Temperature being
above the Economizer Enable Setpoint. Anytime the Economizer is
not modulating for a cooling demand, it will remain at this Minimum
Ventilation Position during Occupied hours. High limit = 100%; Low
limit = 1%; Default = 10%.
Economizer Control Rate
The speed at which the Outdoor Air Damper Actuators are controlled
in the Economizer Mode can be controlled with this setting. The higher
the number, the faster the rate. High limit = 99 seconds; Low limit = 10
seconds; Default = 90 minutes.
Carbon Dioxide Max Economizer
This Setpoint allows you to set the Maximum Position the Economizer
will open if high CO
2
conditions occur in the space. The Maximum
Economizer Position Setpoint is used to limit the amount of Outdoor
Air that will be introduced to the HVAC unit in order to ensure the unit
is operating within its Heating and Cooling design limitations. The
Minimum setting for this Setpoint is the value previously set for the
Economizer Minimum Position Setpoint. High limit =100%; Low limit
= 0%; Default = 100%.
Figure 56: VCM-X Static & Air Setpoints Screen 1
Figure 57: VCM-X Static & Air Setpoints Screen 2