ESIE07-05
The Digital Controller
Part 2 – Functional Description
2–5
3
2
4
5
1
1.3
Main Control Software Features
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Control of evaporator outlet or condenser outlet or both temperature.
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Control of leaving water within a ± 0.1 °C (with a steady-state load).
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Management of sudden load reduction up to 50% with max 3°C controlled temperature obscillation
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Readout of all unit operating main parameters (temperature, pressures, etc.)
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Automatic control of primary evaporator and condenser pumps.
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Condensation control with step logic, single or double fan speed controllers and mixed step+speed
control (speedtroll)
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Control up to 4 steps of cooling tower plus bypass valve with proportional signal 0-10 Vdc
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Setting of a double setpoint with local or remote switch. This function allows to modify the local
setpoint between two values previously settled.
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Setpoint override using an external signal (4-20 mA), outside ambient temperature or evaporator
return temperature.
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Adjustable Max Pull-Down rate reduces under-shoot during loop pull-down.
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Hot Chilled Water Start feature allows the unit startup without any problem also with high
temperature evaporator water.
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SoftLoad feature reduces electrical consumption and peak demand charges during loop pulldown.
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Unit Limiting feature allows to limit electrical consumption based either on current absorption
(current limit (SPN)) or on demand capacity (demand limit).
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Panel mounted 15 key keypad for a rapid interface. Operator can log chiller operating conditions
on the backlight display 4 line by 20 character.
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Four levels of security protection against unauthorized changing.
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Diagnostic System of compressors constituted by the memorization of the last ten alarms, showing
the date, the time and operating conditions at the time the alarm occurred.
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Weekly and yearly start-stop time schedule
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Easy integration into building automation systems via separate 4-20 mA signals for chilled water
reset and demand limiting.
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Communications capabilities for remote monitoring, changing of setpoint, trend logging, alarm and
event detection, via a compatible IBM-PC where is installed MICROPLANT 2.0 software.
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BAS communication capability via Modbus, LonWork, Johnson Metasys
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Remote communications capabilities via modem (up to 8 chillers with Gateway Modem).
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Remote communications capabilities via GSM Modem.
ESIE07-05.book Page 5 Friday, December 21, 2007 3:21 PM
