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GLOSSARY:
ACTUATOR Electromagnetic devices which convert electric current to linear
or rotary motion. This motion may then be used to control
equipment directly, an electro-mechanical actuator, or it can be
used to regulate a gas or liquid pressure as in a CURRENT TO
PRESSURE converter (I/P).
ANALOG INPUT An input which accepts voltage signals between 0 and 5 volts.
These signals are converted by the DE-2500 to engineering
units and compared by the microprocessor to user programmed
safety shutdown and control setpoints. Channels 30-37 and 40-
45 are analog inputs.
ANALOG OUTPUT An output which provides a current between 4-20 milliamps to
external devices to control the compressor. These outputs can
be used to interface directly to electrical actuators or connected
to I/P transducers mechanical actuators.
CAPACITY CONTROL The capacity control of the compressor is accomplished by
reducing the volume of gas moved per compressor cycle. 100%
capacity is the full rated volume of gas compressed per
machine cycle. Capacity control can be done on both
reciprocating and screw compressors using various techniques.
COMPRESSOR CYCLE A compressor cycle is a full rotation of the compressor drive
shaft. A turn of the screw on a screw compressor or a
revolution of the crankshaft on a reciprocating compressor.
CONTROL SETPOINTS These are setpoints programmed by the user which are within
the normal operating range of the equipment and are used to
optimize the function of the equipment. Control setpoints may
also be used to implement corrective actions to prevent
overstress of components or to notify personnel of potential
problems before they become severe enough to cause a
shutdown.
CRANK DISCONNECT The RPM setting at which output # 3 of the power supply will be
de-energized. This will de-energize the starting device.
CRANKING DELAY The time after the auto start command before cranking will
begin. Allows for pre-lube function and starting warning to
personnel. Power supply output # 4 is normally energized
during this time. See PRE-LUBE TIME.
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