ACC-APG001A-EN
25
• BAS Lockout Function
• BAS Capacity Enable function
• Demand Limit Function
Depending on how the controller application is configured, different portions of the capacity limit
control can be active at any time. Because of this, a priority scheme is built into the capacity
limitation function.
If cooling is allowed from “Cooling Lockout BAS – Active” and if Demand Management is
configured for Demand Limit, “Cooling Demand Limit Capacity Enable Setpoint – Active” or
“Heating Demand Limit Capacity Enable Setpoint – Active” will be used to limit the unit capacity
if it is active and “Cooling Capacity Enable – Active” is not limiting capacity. If “Cooling Capacity
Enable – Active” is set to a value less than 100, “Cooling Capacity Enable – Active” has priority.
For capacity limiting values for user selected values, refer to the Appendix section of this
document.
Remote Capacity Control
The Symbio 700 controls support the Remote Capacity Control function, which allows a user to
directly control the unit capacity rather than allowing the internal algorithm to provide control.
The following features/functions can be requested directly via points, rather than relying on
internal temperature or thermostat control sequences:
• Supply Fan Speed
• Cooling Capacity
• Heating Capacity
For Thermostat Controlled equipment, the Thermostat Inputs must be "OPEN" i.e. requesting
"OFF" mode before the Cooling or Heating Capacity requests will be honored.
For Space Temperature controlled equipment, the Heat Cool Mode Request must be set to "Fan
Only" before the Cooling or Heating Capacity requests will be honored.
For each entity, there is an "Enable" point to enable or disable the remote capacity control, and
an analog value point to allow the user to request an analog capacity value. The analog value is
translated to the appropriate value per function.
Supply Fan Speed Command overrides will be honored in all non-Heat or Off modes. When
Supply Fan Speed Command is enabled, and the Supply Fan Speed Command value is 0%, the
system will interpret as an "OFF" mode request, and all active capacity will be set to "Off"; fan,
heating, and cooling.
All equipment safeties and limitations will be in-place while the Remote Capacity Control
functions are being leveraged:
• Minimum fan speeds as defined per active capacity will be maintained
• Compressor Minimum ON/OFF times will be maintained
• All system diagnostics will be maintained.
Emergency and Ventilation Override
This feature has two options for initiating an override request, either through the optional
(future) hardwired Ventilation Override terminals, or by initiating a request through the
Emergency Override Command point, a priority scheme is required to ensure proper equipment
operation.
Ventilation Override (Future)
When configured for the Ventilation Override option, applying 24 volts to one of the three
Ventilation Override inputs manually activates Ventilation Override. Three inputs are provided to
support Ventilation Override functionality:
• Pressurize mode
• Purge mode
BBuuiillddiinngg AAuuttoommaattiioonn SSyysstteemm SSuuppppoorrtt SSeeqquueenncceess
To Next Page
Loading...
