STULZ E
2
SERIES CONTROLLER FOR PERIMETER SYSTEMS OPERATION MANUAL
2
2.2.2 Password Protection
Access to the Info menu and Alarms log is allowed without the
use of a password. The controller is programmed to recognize
predetermined security levels before allowing access to display
screens containing critical variables. Four secured menu levels
(Control, Service, Factory and Confi guration) support unique
passwords that must be entered to access the menu screens
so only authorized personnel may perform modifi cations to the
settings. This Manual covers Information, Control and Service
levels only. The Factory and Confi guration levels are covered
in a separate manual.
2.2.3 Restorable Setpoint Parameters
Upon initial start-up the A/C system operates using the
setpoints programmed by the factory. New operating
parameters may be entered in the Control level and the system
will then operate accordingly. The new setpoints may be stored
as Customer default setpoints in the Service>Save Cfg menu
screen. The primary setpoints entered by the factory still remain
stored in the controller's memory as Factory setpoints.
The setpoints for the system may be re-adjusted in the Control
level at any time. Use the Service>Save Cfg menu screen to
restore the setpoints to the Customer Default setpoint values
or to the original Factory setpoint values.
2.2.4 Weekly Timer Feature
The weekly timer allows the user to set up an operating
schedule to automatically scale back or shut down the air
conditioner during low demand or unoccupied periods. This is
an energy saving feature offering the user the ability to create
an operating schedule tailored to the needs of the building. An
evening (night-setback) schedule may also be created, allowing
the A/C unit to operate at night with relaxed temperature/
humidity setpoints and offsets.
2.2.5 A/C Grouping pLAN Operation
Multiple A/C units, consisting of up to eight (8) STULZ precision
air conditioners equipped with STULZ E
2
Series controllers,
can be connected (grouped) through the pLAN. The pLAN puts
all displays and controllers on a single RS485 connection to
allow information to be exchanged among all the controllers.
Each display and controller has a unique, predefi ned address.
Each controller in a group can be confi gured as “Active”, “Assist”
or “Standby”. Units that are “Active” are used to maintain the
setpoints. Units that are “Assist” are used to step in if the
Active units are unable to maintain the setpoints. Units that
are “Standby” are used as backup units in case of a failure of
either an Active or Assist unit. The role of lead controller can be
assigned to one of the Active AC units. Rotation of the lead unit
function to the next Active unit can be set to occur hourly, daily
at a specifi c time or weekly on a specifi c day at a specifi c time.
This allows the units within the group to be operated for equal
times on a periodic time basis. See section 7.0 for more details.
2.0 DESCRIPTION
2.1 General
The advanced microprocessor based, STULZ E
2
Series
controller is a highly versatile and fl exible A/C system controller.
It is designed primarily for STULZ Precision Air Conditioners.
The controller is equipped with fl exible software capable of
meeting the specifi c needs of the application. The controller
is completely programmed at the factory and therefore, most
applications will require no fi eld set-up. However, the default
setpoints and their ranges are easily viewed and adjusted
from the user interface display. The program and operating
parameters are permanently stored on fl ash memory in case
of power failure.
The controller is designed to manage temperature and humidity
levels to a user defi ned setpoint via control output signals to
the A/C system. Control parameters have variable outputs from
0 to 100% of the full rated capacity. The controller receives
inputs for the measurable control conditions (temperature
and relative humidity) via return air or room mounted sensors.
The internal logic determines if the conditions require cooling,
heating, humidifi cation or dehumidifi cation. Control setpoints
are established to maintain the room's designed conditions.
The controller responds accordingly to changes and controls
the output(s) to the air conditioning system so temperature/
humidity conditions reach the user defi ned control setpoints.
The STULZ E
2
Series controller continually monitors
conditions and maintains setpoints utilizing STULZ’s unique
psychrometric control method. The controller logically
examines the combination of temperature and relative humidity
(dewpoint) and determines the proper control of cooling,
heating, humidification and dehumidification to move the
actual conditions to within the boundaries of the temperature/
humidity setpoints as they would appear on a psychrometric
chart. It avoids scenarios where the cooling unit might both
cool and humidify the air when cooling alone will achieve the
desired result. This control method results in higher operational
effi ciency and shorter component run-times.
2.2 Features
2.2.1 Field Confi gurable
The program for the STULZ E
2
Series controller is field
confi gurable, allowing the operator the capability of selecting
control setpoints specifi c to the application. Operator interface
for the STULZ E
2
Series controller is provided via an attractive,
door mounted user interface display panel. The display panel
has a backlit LCD graphical display and function keys giving the
user complete control and monitoring capability of the precision
cooling system. The menu driven interface provides users
the ability to scroll through and enter various menu screens.
Monitoring of room conditions and A/C system operation is
allowed without entering a password. Modifi cations to the
control setpoints require the use of a password.
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