8
OM
AGSB-5
ms
Milli-second
OAT
Outside ambient air temperature
pLAN
Peco Local Area Network is the proprietary name of the network connecting the control
elements.
Refrigerant Saturated Temperature
Refrigerant saturated temperature is calculated from the pressure sensor readings for each
circuit. The pressure is fitted to an R-134a temperature/pressure curve to determine the
saturated temperature.
Slide
Slide is an abbreviation for the compressor slide valve, which determines the compressor
capacity. It is positioned by the controller such that to unload, it moves toward the main
rotor suction end and discharge gas is bypassed from the rotor discharge back to suction.
Slide Target, Slide Position
See page 14 for explanation of these terms.
SP
Setpoint
SSS
Solid state starter as used on McQuay screw compressors
Suction Superheat
Suction superheat is calculated for each circuit using the following equation:
Suction Superheat = Suction Temperature – Evaporator Saturated Temperature
Stageon/Stageup
Stage On or Stage Up is the act of starting a compressor or fan when another is still
operating. The two phrases are interchangeable and either one can be used depending on
the date of issue of the software. “Start” is the act of starting the first compressor or fan on
a unit.
Stageoff/Stagedown
Stage Off or Stage Down is the act of stopping a compressor or fan when another is still
operating. The two phrases are interchangeable and either one can be used depending on
the date of issue of the software. “Stop” is the act of stopping the last compressor or fan on
a unit.
VDC
Volts, Direct current, sometimes noted as vdc
VFD
Variable Frequency Drive, a device used to vary an electric motor’s speed.
Unit and Circuit Controller Description
Hardware Structure
The controllers are fitted with a 16-bit microprocessor for running the control program.
There are terminals for connection to the controlled devices (for example: solenoid valves,
expansion valves, chilled water pumps). The program and settings are saved permanently in
FLASH memory, preventing data loss in the event of power failure without requiring a
back-up battery. It also has optional remote communication access capability for a BAS
interface.
Summary of Contents for AGS 206A
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