Orion System System Manager TS II In-House - Manual (Page 55)

SMTS II Technical Guide
VCM, VCM-X & VCB-X Controllers
55
VCB-X Controllers
VCB-X Static & Air Setpoints
Static Pressure 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 to the Static Pressure Setpoint. The Duct Static
Pressure is maintained at this setpoint anytime the Main Fan is running.
High limit = 3.00”WG; Low limit = 0.10”WG; Default = 1.50”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 setpoint. High limit = 0.50”WG; Low limit = 0.01”WG; Default
= 0.10”WG.
Building Pressure Setpoint
The Building Pressure is maintained at this setpoint while the Main Fan
is running. See detailed explanation that follows. High limit = 0.20”WG;
Low limit = -0.20”WG; Default = 0.02”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 that follows. High limit =
0.10”WG; Low limit = 0.01”WG; Default = 0.01”WG.
Building Pressure Control
The VCB-X can maintain Building Static Pressure anytime the Supply
Fan is operating. A Building Pressure Transducer must be connected to
the VCB-X EM1 Expansion Module. The following are the available
control options.
Direct Acting Building Pressure Control
• On/Off Exhaust Fan— If an On/Off Exhaust Fan is
being used, a relay output must be confi gured for
“Exhaust Fan”. This relay will energize whenever the
Building Pressure rises above the Building Pressure
Setpoint by the Deadband amount. The relay will de-
energize when the Building Pressure falls below the
Building Pressure Setpoint by the Deadband amount.
• Exhaust Fan VFD or Modulating Exhaust
Damper— If confi gured for Modulating Exhaust, a user-
adjustable voltage output (AOUT1 – Building Pressure
Output on the VCB-X EM1 Expansion Module) will
be used to control this fan or damper. An Exhaust Relay
can be confi gured if necessary to enable the fan or
damper. Whenever the Building Pressure rises above
the Building Pressure Setpoint by the Deadband amount,
the Exhaust Fan Relay will energize and the Modulat-
ing Signal will activate to control to the Building
Pressure Setpoint. If the Building Pressure falls below
the Building Pressure Setpoint by the Deadband amount,
the Modulating Signal will modulate towards 0% as it
attempts to maintain the Building Pressure Setpoint.
The Exhaust Fan Relay is energized whenever the
Modulating Signal is above 0%.
Reverse Acting Building Pressure Control
• Outdoor Air Damper— If this option is confi gured,
the VCB-X will use the user-adjustable Economizer/
Outdoor Air Damper output signal (AOUT2 –
Economizer Control Signal) to maintain the Building
Pressure Setpoint. Whenever the Building Pressure
falls below the Building Pressure Setpoint by the
Deadband amount, the modulating Economizer Output
Signal will modulate the damper open to control to
the Building Pressure Setpoint. If the Building Pressure
rises above the Building Pressure Setpoint by the
Deadband amount, the damper will modulate towards
closed as it attempts to maintain the Building Pressure
Setpoint. When this option is selected, no Economizer
free cooling or CO
2
IAQ operation will be available.
• Supply Fan VFD – Contact WattMaster regarding this
Reverse Acting Building Pressure Control option. It
should not be used in most applications. If this option
is selected, the user-adjustable Supply Fan VFD Output
(AOUT1 on the VCB-X) will be used to control the
Supply Fan VFD to maintain the Building Pressure
Setpoint in similar fashion to the Outdoor Air Damper
control described above.
Setpoints for Unit 0001
Static Pressure Setpoint
Building Pressure Setpoint
1.50
0.02
“Wg
Static Pressure Deadband
Building Setpoint Deadband
0.10
0.01
Static & Air Setpoints
“Wg
“Wg
Page 3 of 4
“Wg
Figure 105: VCB-X Static & Air Setpoints Screen 3