Specifications

16 • HVAC Control 026-1728 Rev 0 25-AUG-2011
the unit with the active input will stop its cooling or
heating, fan, and economizer control (disables the
unit).
The HVAC Control temperature values will sup-
port Dixell and CPC sensors in both Fahrenheit and
Celsius engineering units.
6.3.1. HVAC Control — Physical In-
puts and Outputs-Default Set-
up
6.3.2. Cooling Control
Cooling control will have the ability to manage up
to two stages of cooling using a control temperature.
6.3.2.1. Monitoring and Lockout Tem-
peratures
There will be three monitoring temperatures, Sup-
ply, Return, and Outside; however, Return and Out-
side have alternate roles. The return temperature is the
backup control temperature and the Outside is used in
the cooling lockout.
LockOut:
Prevents heating from turning on if the outside
temperature is above a certain value. Likewise, the
cooling should not be allowed to turn on if the outside
air is below a certain value.
6.3.2.2. Control Temperature
The application will determine the control temper-
ature from Space Temperature 1 or the average of
Space Temperature 1 and 2 if the space temp 2 is de-
fined. If Space Temperature 1 is the only temperature
used for controlling and it fails, the backup tempera-
ture will be the return temperature. If controlling from
the average mode and either of the space temperatures
fail, the backup will become the other space tempera-
Inputs Type
RTU 1 Space Temperature 1 Anlg
RTU 1 Space Temperature 2 Anlg
RTU 1 Supply Temperature Anlg
RTU 1 Return Temperature/Out RH
RTU 1 could be configured to Return
Temperature/Out RH/CO2
Anlg
RTU 1 Fan Proof Dig
Emergency Shutdown 1 Dig
RTU 2 Space Temperature 1 Anlg
RTU 2 Space Temperature 2/OAT
RTU 2 could be only configured to Space
Temperature
Anlg
RTU 2 Supply Temperature Anlg
RTU 2 Return Temperature/CO2
RTU 2 could be configured to Return
Temperature/Out RH/CO2
Anlg
RTU 2 Fan Proof Dig
Outside Temperature Anlg
Table 6-7 -HVAC Control Input
Outputs Type
RTU 1 Fan RO
RTU 1 Cool1 RO
RTU 1 Cool2 RO
RTU 1 Heat1/Rev Valve RO
RTU 1 Heat2/Emerg HT RO
RTU 2 Fan RO
RTU 2 Cool1 RO
RTU 2 Cool2 RO
Table 6-8 -HVAC Control Output
RTU2 Heat1/Rev Valve RO
RTU Heat2/Emerg HT RO
RTU 1 Economizer AO
RTU 2 Economizer AO
Input Description Function
Supply Temp Supply Temperature Monitoring
Return Temp Return Temperature Monitoring/
Control
Outside Temp Outside Temperature Monitoring/
LockOut
Table 6-9 - Monitoring and Lockout
Table 6-8 -HVAC Control Output