30
GLOSSARY OF TERMS
AC
Alternating Current. The voltage, and therefore current, constantly oscillates
positive and negative. For North America, the line frequency is 60 Hz. Some
other areas of the world use 50 Hz.
Across-the-line (XL)
Applying 100% of line voltage to a motor during startup and run. A simple
large relay with a contact for each power phase (for 3 phase) is used to
control the motor OFF/ON.
Analog
A signal that varies in some respect (voltage, current, frequency) in order to
convey the value of some real world information (i.e. pressure, flow,
temperature etc). A control system can take action based on the value of
such a signal. Internally, the signal will be converted to some number based
on the value of the signal.
Automatic lake screen
(ALS) A screen on the intake flume of the pump station, between the
irrigation pond and the wet well, which is designed to be self cleaning by
using a jet of clean water spraying from the inside-out during use.
Booster
A pump designed to increase the pressure of a pressurized irrigation line.
This is usually used to move pressurized water from a lower to higher
elevation area of the golf course.
Calibration
The act of or specific values used to scale the output of a measurement
device to read real-world values.
Canned turbine
See vertical turbine.
Chemical injection
The process of adding chemicals to irrigation water to fertilize or medicate
turfgrass.
Combo
A capacity level representing a predefined group of pumps on a station.
Normally Combos are defined as follows:
Combo 1
Normally the PM pump.
Combo 2
Lead pump. Normally the VSP.
Combo 3
Lead pump and first lag pump.
Combo 4
Lead pump and two lag pumps.
Control valve
A valve designed to automatically open/close in order to maintain a specific
setpoint pressure, flow, or level.
Control variable
A value that a control system monitors in order to perform some useful
function.
Conventional
Refers to fixed-speed pump systems using a pressure reducing valve for
pressure control.
CPU
Central processing unit. The part of the PLC that stores and allows
manipulation of the program, in conjunction with an EEPROM chip.
Cycle time
The number of times an hour that a pump (PM or main pump) cycles on and
off.
Cycling
This condition occurs when conditions require a pump to start if no pump is
running, but require a pump to stop if a pump is running. This is excessive
starting and stopping of one or more pumps and can be damaging to the
