Orion System VCM-X Modular E-BUS - Manual (Page 50)

Zone
Zone
INPUTS & OUTPUTS
VCM-X Modular E-BUS Controller Technical Guide 50
VCM-X E-BUS Controller Inputs
VCM-X E-BUS Controller Inputs
AI1 - Space Temperature Sensor Input
If you want to generate Occupied or Unoccupied Heating and Cooling
demands based on Space Temperature, select this Sensor for the HVAC
Mode enable. The Space Temperature Sensor can be used for Night Set-
back control regardless of the HVAC Mode Sensor selected. If the Space
Temperature Sensor used is equipped with the optional Push-Button
Override Feature, this input will detect user overrides from Unoccu-
pied back to Occupied operation for a user-adjustable amount of time.
This Sensor is not required for Cooling Only HVAC units confi gured
for Supply Air Temperature control as the HVAC Mode Enable Sensor
unless Night Setback operation is required. The Space Temperature can
also be confi gured to reset the Supply Air Temperature Setpoint. The
Space Temperature Sensor is the only Sensor that can be used for Night
Setback operation during the Unoccupied Mode.
AI2 - Supply Air Temperature Sensor Input
The Supply Air Temperature Sensor is the default HVAC Mode Enable
Sensor. For typical VAV units that are Cooling Only with Morning
Warm-up, this Sensor should be confi gured as the HVAC Mode Enable
Sensor. Heating will only occur during Morning Warm-up. After Morn-
ing Warm-up expires, the Supply Air Temperature will be maintained
at the Supply Air Temperature Cooling Setpoint. The HVAC unit must
always have a Supply Air Temperature Sensor installed.
AI3 - Return Air Temperature Sensor Input
If you want to generate occupied Heating and Cooling demands based
on Return Air Temperature, select this Sensor as the HVAC Mode En-
able Sensor. The Return Air Temperature Sensor is also used to initiate
or cancel the Morning Warm-up Period on VAV-confi gured units. This
temperature must be at least 5°F above the Outdoor Air Temperature to
allow Economizer Cooling operation.
AI4 - Outdoor Air Temperature Sensor Input
The Outdoor Air Temperature is used to lock out Heating or Cooling to
conserve energy at whatever temperature you deem appropriate for each
Mode of Operation. The Outdoor Air Temperature Sensor can also be
used to provide Low Ambient Temperature Protection in the building.
If the Outdoor Air Temperature is below the Low Ambient Temperature
Setpoint, the Preheat Relay Output will be maintained during Occupied
operation and will not be allowed to stage off unless the Supply Fan is
turned off. When using 100% (MUA Units) Outdoor Air applications,
the Outdoor Air Temperature Sensor should be confi gured as the HVAC
Mode Enable Sensor. The Outdoor Air Temperature Sensor is also used
in combination with the Outdoor Air Humidity Sensor for Dewpoint
calculations. For MUA applications with a Heat Wheel, the Outdoor
Air Temperature Sensor is mounted downstream of the Heat Wheel.
AI5 - Suction Pressure Signal Input
The Suction Pressure Sensor signal is connected to this input. The
Suction pressure Signal is supplied either from the VCM-X Expansion
Module “PR OUT” terminal when a standard non-digital compressor is
used or from the “P6” terminal of the Copeland
® Compressor Digital
Controller when a digital compressor is used. This Suction Pressure
Sensor signal input is required when using Dehumidifi cation with DX
Cooling units. The VCM-X E-BUS Controller converts the Suction
Pressure reading to Suction Temperature. This calculated Evaporator
Coil Temperature is considered to be the Saturation Vapor Pressure of
the refrigerant leaving the evaporator coil. In most cases, the Supply Air
Temperature leaving the Evaporator coil will be 10°F to 15°F higher
than the calculated Evaporator Coil Temperature.
NOTE: All temperature Sensors must be Thermistor Type III which
provide 77.0°F @ 10K Ohms Resistance.
AI6 - Duct Static Pressure Sensor Input
This special phone jack-style input connection accepts a Duct Static
Pressure Sensor input modular cable. The Duct Static Pressure Sensor
reading is used to determine current Duct Static Pressure. This Static
Pressure reading is used to control the output signal supplied to the Sup-
ply Fan VFD or Zoning Bypass Damper Actuator. If you have confi gured
the HVAC unit for Constant Volume operation, this Sensor is optional.
If it is installed on a Constant Volume unit, it will not affect operation,
but rather will be used as a status-only reading.
AI7 - Space Temperature Sensor Slide Adjust or
Remote SAT Reset Signal Input
AI7 on the VCM-X E-BUS Controller is a dual-purpose input. It can be
used for the Space Sensor Slide Adjust option or for connection of the
Remote Supply Air Setpoint Reset Signal option. Only one or the other
can be used, not both.
Space Temperature Sensor Slide Adjust
If the Space Temperature Sensor being used has the optional Slide Ad-
just feature, its AUX output is connected to this input. The Slide Adjust
control is used to vary the HVAC Mode Heating and Cooling Setpoints
by a user-confi gured maximum amount. The Slide Adjustment adjusts
whichever Temperature Sensor has been confi gured as the HVAC Mode
Enable Sensor, even if that Sensor is not the installed Space Temperature
Sensor.
If Space Temperature or Return Air Temperature is confi gured as the
SAT/Reset Source, the Slide Adjustment adjusts both the HVAC Mode
Enable Heating and Cooling setpoints and the SAT/Reset Source Heating
and Cooling setpoints simultaneously by a user-confi gurable maximum
amount.
Remote Supply Air Temperature Reset Signal
When a 0-5 VDC Remote Supply Air Temperature Reset Signal is to be
used, the controller must be confi gured for it, and the Room Sensor Slide
Offset setpoint must be set to zero for this option. If the slide offset is not
set to zero, the Supply Air Temperature Reset will not function.
The Remote Supply Air Temperature Reset signal must be confi gured
so that its setpoint will be at the coldest Supply Air Temperature, or 0
VDC, and so that its setpoint will be at the warmest Supply Air Tem-
perature, or 5 VDC.
The jumper AI7 must be set to 0-10V regardless of whether the control-
ler is confi gured for 0-5 or 0-10VDC operation. See the wiring diagram
on page 14 for details.