Daikin MicroTech, Operation And Maintenance

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OM 1280-2 • MICROTECH UNIT CONTROLLER 10 www.DaikinApplied.com
Description of Operation
Description of Operation
State Programming
The MicroTech UVC takes advantage of “state” machine
programming to define and control unit ventilator operation. A
“state” defines a specific mode of operation for each process
within the unit ventilator (e.g., heating, cooling, etc.) and contains
the specific decision logic and sequence of operation for each
mode. This eliminates some of the most common problems
associated with control sequences such as the possibility of
simultaneous heating and cooling, rapid cycling, etc.
The UVC states and super states are used to define
the “normal” unit modes, such as Off, Night Purge, Fan
Only, Emergency Heat, Auto, Cool, Heat, and Active
Dehumidification. The UVC also sup ports several
“special purpose” unit modes such as Purge, Pressurize,
Depressurize, and Shut down, which can be forced via a
network connection and override typical UVC operation.
The state diagrams presented in the following sections
consist of several features including super states, states,
transition logic and methods of entry to the state. Super
states are used as a means to group two or more related
states into a single control function. There are three super
states: Heating, Cooling and Emergency Heat. The states,
are where all the actual work takes place. Within each state
the UVC enables PI-loops and other logic sequences required
to control unit ventilator operation within that particular
state, while other functions and PI-loops not needed during
that state may be disabled. The transition logic represents
questions used by the UVC to determine which state should
be made active. These transition questions are constantly
being monitored by the UVC, which allows the unit to switch
between modes as it deems is necessary. The possible
methods of entry to each state or super state vary. Entry
into some states must be forced by an input through the
LUI keypad, ServiceTools software, or a network input.
Some states will only be entered automatically from a super
state or other state, while some can be entered manually or
automatically. The unit configuration settings may be changed
using available ServiceTools software.
NOTE: Not all states or modes are available for all UV
configurations, and some states (such as Active
Dehumidification) are optional.
Figure 2: Complete UVC—State Diagram
LUI Input
Network Input
Auto
Mode
Off
Mode
Night Purge
Mode
Fan Only
Mode
Heat Mode
Manual/Forced Transition
One-way Automatic Transition
Two-way Automatic Transition
Econ
Mode
Econ Mech
Mode
Can’t Cool
Mode
Mech Cool
Mode
Cool Mode
Auxiliary Heat may be used if available
Emergency Heat
Auxiliary Heat may be
used if available
Refer to “Cool Mode Super State Diagram” on page 17
Refer to “Heat Mode with Defrost Super
State Diagram” on page 16
Refer to “Emergency Heat
(Super State)” on page 15