ACC-SVP01B-EN • BCI-I Integration Guide 9
BCI-I Configuration
Periodic Update of BAS Values
The BCI-I device requires the BAS system to provide a periodic update to the sensor values. This
is required to protect against a loss of communication between the BAS and the BCI-I. By BACnet
definition, the present value of the object will maintain the last value written to it, regardless of the
amount of time that has elapsed since the last write. If communication is lost for several minutes
or longer, the present value of BAS-supplied sensor objects may no longer represent the current
state of environmental conditions. This may result in decreased occupant comfort and damage to
building systems.
BAS Communication Failure
The BCI-I is designed to minimize communication failure mode. It does this by monitoring the
length of time that has elapsed since the last write to the present value of the sensor object. If the
length of time exceeds a predefined limit, the BCI-I will place the object into the fault state and revert
to a unit-supplied sensor value for control. At power up, the sensor objects are set to a fault state
and they will remain in this state until a write is detected. The minimum periodic refresh rate for
the objects is defined in Ta bl e 3 , p . 24 . The following list is a set of sensor values that can be
supplied by the BAS:
• Space Static Pressure BAS
• Space Air Temperature BAS
• Discharge Air Temperature BAS
• Duct Static Air Pressure BAS
• Outdoor Air Temperature BAS
• Outdoor Air Humidity BAS
• Outdoor Airflow BAS
• Space CO2 Concentration BAS
• Space Humidity BAS
Input/Output Commands and Calculations
This section will provide the following information about certain inputs and outputs that perform
unique control commands and calculations:
• System control command
• Filter timer and diagnostic reset commands
• Setpoint calculations
System Control Command
Binary Output Object 1, has a special importance in the system. The object allows the BAS to
command the unit to run in a local or BAS control mode. When the present value property of the
object is set to Local Control, the IntelliPak unit will enter local control and ignore BAS supplied
values. In this mode, the unit will use local sensor and setpoint values. When the object present
value property is set to BAS Control, the IntelliPak unit will use the values supplied by the BAS
system for unit control.
Filter Timer Reset Command
The BCI-I uses the Filter Runtime Hours object (AI 6) to generate a diagnostic when its present value
is greater than the Filter Runtime Hours Setpoint, (AV 1) present value. The procedure for resetting
the timer is as follows:
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