803 B – 04/11 D – pag. 5/24
Microtech II Plus controller
Microtech II Plus device is installed as standard on all the units; it can be used to alter unit set points and control
commands. A display illustrates the machine's operating status and programable parameters (setpoints) e.g.
temperatures and pressures of fluids (water, refrigerant). Device controls maximise the McQuay chillers energy
efficiency and reliability characteristics. It uses sophisticated software with predictive logic to select the most
energy efficient combination of compressor. The compressors are automatically rotated to ensure equal operating
hours. Microprocessor device protects critical components in response to external signals from its system sensors
measuring: motor temperatures, refrigerant gas and oil pressures, electrical supply and evaporator.
Control section - main features:
•
Management of the compressor capacity slide according to the distributed multiprocessor logic system
•
Chillers enabled to work in partial failure condition thanks to the distributed multiprocessor logic system
•
Full routine operation at condition of:
High thermal load
High evaporator entering water temperature (start-up)
•
Display of evaporator entering/leaving water temperature
•
Display of condensing-evaporating temperature and pressure, superheat temperature for each circuit
•
Leaving water cooled temperature regulation (also available entering water regulation). Temperature
tolerance=0,2°C
•
Compressors and evaporator/condenser pumps hours counter
•
Display of Status Safety Devices
•
Start up numbers and compressors working hours equalization
•
Excellent management of compressors load
•
Automatic re-start in case of power supply interruption
•
External signal demand limit 0÷100%
•
Soft load: starting load limitation (25÷100%) time based
•
External air reset
•
Current limitor
•
High evaporator temperature start
Safety for each refrigerant circuit
High pressure (pressure switch)
Low pressure (pressure switch)
Compressor thermal
High Discharge Temperature on the compressor
Phase Monitor
Star / Delta Transition Failed
Low Delta Pressure between Suction and Discharge
System security
A serious alarm input (stops the unit)
A flow controller input (stops the unit)
A pump thermal input (stops the unit)
Remote on/off input without alarm signaling
Regulation type
Stabilized PID Proportional - Integral – Derivative regulation on the evaporator input probe for a perfect water
regulation (max
∆
T = ± 0,2°C)
