These selections provide the logic for controlling the operation of the application. The Unit Enable logic includes the option to delay startup after controller restart (Power Fail Restart).
The selection options for Optional Features are:
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Smoke Control Support (UL-864-UUKL): This option adds the Emergency Mode Network Input and the Smoke Control Sequencing for UL-864-UUKL State Generator module. In the State Selection Table, you can create state values for each Output Controller to provide normal control, pressurize, depressurize, purge, or shutdown. For example, if the Emergency Mode Network Input is set to shutdown, you can set all of the Output Controller states to the desired condition in the State Selection Table.
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Unit Enable: This option determines whether the application operates based on the Network Input (BV). If Unit Enable Switch is selected, then when the Network Input does not have a valid command from the network, it is considered unreliable (and the unit is enabled). If both BI and BV are selected, the state of both must be Enable for the unit to operate (that is, either input can be in a shutdown state to cause the unit to stop).
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Unit Enable Switch (BI): This option determines whether the application operates based on the Hardware Input (BI). If Unit Enable is selected, then when the Network Input does not have a valid command from the network, it is considered unreliable (and the unit is enabled). If both BI and BV are selected, the state of both must be Enable for the unit to operate (that is, either input can be in a shutdown state to cause the unit to stop).
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Power Fail Restart: This feature is available as part of the Unit Enable Determination State Generator module. When this option is selected, after a restart (power cycle, transfer to the controller, or manual restart command), the application is held in the shutdown state for the Power Fail Restart Time (default = 60 seconds).
- Setup and Setback (G36): This option adds a network BI for both SETUP and SETBACK which are set to true whenever the zones it serves indicate the system should be in setup or setback mode. The supply fan enables whenever the SETUP is true. If the system has any reheat boxes on perimeter zones, then the supply fan also starts when the SETBACK is set to true, otherwise it has no effect.
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Trim and Respond (G36):VAVs may send requests to the
AHU to either decrease the discharge air temperature or increase the discharge air
pressure.
- DAT Setpoint Reset (G36): The effective DAT setpoint (TR-DAT-EFF-SP) is always between TR-DAT-SP-MIN and TR-DAT-SP-MAX. The maximum value of the setpoint is set to progressively larger values until it reaches TR-DAT-SP-MAX until it responds to VAV requests (network AI DAT-REQUESTS) by lowering the maximum value. The actual effective setpoint will be reset based upon the outdoor air temperature (OAT).
- DSP Setpoint Reset (G36): The effective DSP setpoint (TR-DSP-EFF-SP) reduces down towards TR-DSP-SP-MIN until it either reaches the minimum value or enough DSP requests (network input DSP-REQUESTS) are received. When enough requests are received the AHU responds by increasing the setpoint until there are no longer too many requests, or it reaches the maximum setpoint TR-DSP-SP-MAX.
- AHU Alarming (G36): This option adds alarms for fan maintenance, large filter pressure drops, and high and low building static pressures.
- Automatic Fault Detection and Diagnostics (G36): This option adds logic which assesses AHU performance by comparing network BAS inputs and outputs to a subset of potential fault conditions. The subset of potential fault conditions that is assessed at any point depends on the operating state (OS) of the AHU, as determined by the position of cooling and heating valves and the economizer damper (OAD-O). Time delays are applied to the evaluation and reporting of fault conditions to suppress false alarms. Fault condition which pass these filters are reported to the engine along with a series of possible causes.
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Request Generation (G36): Adds AO network outputs to
be sent to chillers and boilers. They include CLG-PLANT-REQ and HTG-PLANT-REQ which
request to enable the chiller or boiler, and they include CLG-RESET-REQ and HTG-RESET-REQ
which request the chiller or boiler to reset their supply pressure or temperature.
- Request Accumulation (G36): Adds logic to help identify whether the AHU is sending so many requests that it is driving trim and respond for the chillers or boilers.
- System OK (G36): Adds logic which sets a BO output (AHU-OK) that is true whenever the system in proven on, and its temperature or pressure setpoints for at least 5 minutes, and is ready and able to serve its load. The value is also set to false whenever there are Level 1 through 3 alarms.