The
models PAC-30U and PDC-30 proximity bin level switches are
solid state point level devices used to detect the absence
or presence of bulk solids. The compact configuration makes
this product ideal for tight spaces or low cost level detection.
As material comes in contact with, or in close proximity to,
the PAC-30U or PDC-30, an internal solid state switch is activated.
The PAC-30U is AC operated (20-265 VAC) and is universal in
that it is switch selectable for either normally open or normally
closed operation. The PDC-30 is DC operated (10-40 VDC) and
is available in either PNP or NPN configuration, each of
which can be wired in either a normally open or normally
closed operation mode.
The
PAC-30U and PDC-30 are RF capacitance-type level controls,
which operate by detecting the electrical effect of the surrounding
material such as air, plastic pellets or powders. A radio
frequency is applied to the proximity switch sensing region
and is continually analyzed to determine the influence of
the surrounding environment. Since all materials have dielectric
constants and conductance values that are different from
that of air, the resultant impedance seen by the radio frequency
changes whenever material approaches or contacts the sensing
region. This influence is measured within the circuitry and
compared with the reference point set by the sensitivity
adjustment, which determines how much influence must be present
before the output changes.
Optional
Mounting Well
Specifications
Model
PAC-30U:
Housing:
Thermoplastic
Polyester
Enclosure
Protection:
IP67
(NEMA 4 equivalent)
Power
Requirements:
20-265
VAC, 45-65 Hz
Mounting
Thread Size:
M30
x 1.5
Sensing
Distance:
4
to 25 mm adjustable
Indicator:
LED,
yellow
Output:
Normally
Closed or Normally Open, Switch Selectable
Leakage
Current:
<2.5
mA
Load
Current:
10-500
mA
Frequency
of Operating Cycle:
25
Hz
Operating
Temperature:
-13° to
176° F (-25° to 80° C)
Electrical
Connections:
Cable,
6ft(1.8m), 18-20 AWG
Max. Pressure:
1.4 psi
Max. Pressure:
(with mounting well)
125 psi
Approvals:
UL/CSA
General Purpose; CE Mark
Model PDC-30:
Housing:
Thermoplastic Polyester
Enclosure Protection:
IP67 (NEMA 4 equivalent)
Power Requirements:
10-40 VDC
Mounting Thread Size:
M30 x 1.5
Sensing Distance:
4 to 25 mm adjustable
Indicator:
LED, yellow
Output:
13-8231, NPN (sinking)
13-8241, PNP (sourcing)
Consumption:
<10.0 mA
Load Current:
0-200 mA
Frequency of Operating Cycle:
100 Hz
Operating Temperature:
–13° to 176° F (-25° to 80° C)
Electrical Connections:
Cable, 6ft(1.8m), 18-20 AWG
Max. Pressure:
1.4 psi
Max. Pressure:
(with mounting well)
125 psi
Approvals:
CE Mark
Warranty
Monitor
Technologies warrants each proximity switch it manufactures
to be free from defects in material and workmanship under
normal use and service within two (2) years from the date
of purchase. The purchaser must give notify Monitor of any
defects within the warranty period, return the product intact,
and prepay transportation charges. The obligation of Monitor
Technologies LLC under this warranty is limited to repair
or replacement at its factory. This warranty does not apply
to any product which is repaired or altered outside of Monitor
Technologies' factory, or which has been subject to misuse,
negligence, accident, incorrect wiring by others, or improper
installation.
DOC-000453A Rev.5.01302009
Spotlight: True Fail Safe Level Switch
TrueCap® MK-2
Advanced RF Capacitance Level Probe
The TrueCap® Model MK-2 RF Capacitance
point level probe is designed to provide a superior and stable sensitivity
threshold making it suitable for a variety of powder / bulk solids
and some liquid or slurry applications.
Advanced features of the
Model MK-2 include: > Automatic immunity to material build-up on the
probe by its driven shield design > Push-button calibration > Enhanced temperature
compensation >
Maximized reliability via smart sensing algorithms like “self-validating” fail-safe
protection > Visible status LED on ordinary loc units > Versatility through a variety of configuration
options including: hazardous location version, split architecture
design, quick-connect process connection, stub probe, cable extensions,
solid extensions, Nylon® probes, Ryton® - equiv. probes,
etc.
A practical application for the TrueCap would be to use this level sensor where
a residual material build-up on a different sensor would cause a false
material level indication.
Principle of Operation for the TrueCap RF Capacitance Level Probe:
The vessel
wall and the active probe element establish an impedance reference between each
other when exposed to air which has a dielectric constant of 1. When materials
with a dielectric constant greater than 1 are in close proximity to the probe,
the impedance of the sensing field between the sensor and the vessel
wall will change. Once the amount of change exceeds a threshold that
was electronically determined during the calibration process, an
output relay will either be energized or de-energized depending upon
the position of the fail-safe selector on the probe’s electronic
circuit board. A change of as little as .5 pico-farad is all that
is necessary for the probe to sense the presence of material.
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