FUTEK IPM500 (D500) Digital Display - Manual (Page 53)

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Deviation limits are programmed by entering
menu item dEU1b for Alarm 1 and dEU2b for
Alarm 2. The deviation band will be equal to
two limits.
Display Blank
A rear panel input which blanks the display
when the input is tied to logic ground by a
switch or 0V is applied (logic level true). The
meter display will light when the input is
open or is held at +5V (logic level false).
Extended Meter
A digital panel meter with an enhanced microcomputer that provides added
capabilities, specifically linearization of nonlinear inputs and display of rate of
change from successive readings.
Full Scale The maximum input signal range for which the meter has been configured. For
example, the most sensitive full scale for the load cell meter is ±20 mV (signal
range from -20 mV to +20 mV).
Function Reset
A rear panel control input which resets Peak, Valley and any latched alarms
when the input is tied to logic ground by a switch or 0V is applied (logic level
true). To reset the value again, the input must be open or 5V applied (logic
level false) and then set low.
Ground Loop
A closed conductive path in external ground wiring that allows stray currents to
flow in ground wiring, creating ground noise. The meters in this manual
minimize ground loop problems by mutually isolating the grounds associated
with meter power, signal input, and all output and communication options.
Jumper A push-on component which provides a short between two adjacent posts on a
circuit board. Jumpers are used to configure signal conditioner boards for
specific signal types and full scale ranges, and to configure power supply and
communications boards for various modes of operation. Unused jumpers are
stored by pushing one side over an unused post.
Hysteresis Band
A band which controls relay action sym-
metrically around a setpoint. The relay
closes (or opens) when the reading goes
above the setpoint plus one hysteresis limit,
and opens (or closes) when the reading
falls below the setpoint less one hysteresis
limit. A narrow hysteresis band is often
used to minimize relay chatter around a
setpoint due to electrical noise or signal
feedback caused by load switching. A wide
hysteresis band can be used for control applications, such as turning on a fill
pump when the tank level has reached a lower limit and shutting off the pump
when the tank level has reached an upper limit. The hysteresis band will be
equal to two hysteresis limits.