Thermo Scientific APEX 100, User Manual

Page: 397 / 442

Thermo Scientific APEX User’s Guide
Page 397
Glossary
Term Definition
QAT The Quality Assurance test—one of the detector’s
quality-control functions.
QNR Quadrature noise-reduction filter
RAM Random-access memory
Reject device Any mechanical device downstream of the search head
that allows contaminated products to be separated
from uncontaminated products. In a typical conveyor
application, “Reject 1” is the main reject device and
“Reject 2” the secondary reject device.
RFI Radiated frequency interference
RO In the Modbus registers, a read-only register.
R threshold Electrically conductive materials and many food
products, by nature, are electrically conductive. Salt-
and moisture-content combine to produce resistive
effects that must be overcome in order to detect small
metallic contaminants. The R threshold is a noise
threshold for resistive signals. Signals above the
threshold usually indicate product or metal
contaminant signals. Excessive resistive signals could
indicate external noise (such as VFD and EMI noise),
ground loops, static, and so on is present in the area
around the metal detector.
RTU Remote terminal unit
R/W In the Modbus registers, a read/write register.
Rx Pharmaceutical application
Search head The large rectangular box with a hole in the middle
through which products are passed to be tested for the
presence of metallic contaminants. Inside, the
magnetic field created by a pair of balanced coils is
disturbed by the passage of metal, allowing the
detector’s circuitry to tag the product as
contaminated.
SF-NB Speed filter–narrow band
SF-WB Speed filter–wide band
Speed filter The speed filter is a narrow-band pass filter that
rejects most background noise, but still allows a
maximum metal signal from the search head to be
processed by the detector.