Specifications are subject to change without notice (25.06.99) 1
Type: Refraction principle
Housing material
Tip material
Light source
Output type
Connection
Level Sensors
Product Description
Optical level probe with
modulated infrared light for
detection of liquids. Self-
contained unit has built-in
amplifier. Separate transmit-
ting and receiving elements
sealed behind the tip.
Designed for direct mounting
through the wall of a tank.
The polysulphone tip is espe-
cially resistant to most acids
and bases.
Type Selection
Housing material Tip material Ordering no. Ordering no. Ordering no. Ordering no.
NPN, Make & NPN, Make & PNP, Make & PNP, Make &
break switching break switching break switching break switching
Cable M12 Plug Cable M12 Plug
Stainless steel Polysulphone VPA1MNA VPA1MNA-1 VPA1MPA VPA1MPA-1
Stainless steel Glass VPA2MNA VPA2MNA-1 VPA2MPA VPA2MPA-1
Nickel plated brass Polysulphone VPB1MNA VPB1MNA-1 VPB1MPA VPB1MPA-1
Nickel plated brass Glass VPB2MNA VPB2MNA-1 VPB2MPA VPB2MPA-1
Specifications
Rated operational voltage 10 - 40 VDC
Ripple ≤10 V
Output current
Continuous ≤200 mA
No-load supply current ≤7 mA
Voltage drop ≤2.5 VDC
Protection Reverse polarity,
short circuit, transients
Ambient light ≤50.000 lux
Transient voltage 1 kV
Delay after power-on 20 ms
Operating frequency ≤30 Hz
Indication for
Output ON LED, yellow
No LED indication on plug types
Sensing accuracy
Liquid level difference Horizontal mounting: ± 5 mm
LED indication on plug types Vertical mounting: ± 2.5 mm
Pressure ≤10 bar at +60ºC (+ 140ºF)
Environment
Degree of protection IP 67
Operating temperature -20° to +80ºC (-4° to +176ºF)
Storage temperature
-40° to +100ºC (-40° to +212ºF)
Liquid temperature +100ºC (+212ºF) for ≤60 s
Housing material Stainless steel or
nickel plated brass
Cable 2 m, 4 x 0.3 mm2, grey, Ø 5.2
oil resistant PVC
Resistance ≤100 Ω, extension possible
Weight 90 g
Tightening torque
Stainless steel 30 Nm
Nickel plated brass 30 Nm
External thread 3/8” (ISO 228/1)
CE-marking Yes
Types VP, Modulated, Metal Housing
Optical
Ordering Key VPB1 M NA-1
• Modulated light
• Built-in amplifier
• Output: NPN or PNP, 4-wire (NO & NC)
• Housing: Stainless steel or nickel plated brass
• Tip: Polysulphone or glass
• High chemical resistance to most acids and bases
• Liquid and electrical circuit completely isolated
• Power supply: DC models 10 to 40 VDC
2Specifications are subject to change without notice (25.06.99)
Mode of Operation
The probe contains IR trans-
mitter, receiver and amplifier
with open collector NPN or
PNP output. The light source
is a Ga-As diode emitting
modulated, infrared light in
short pulses.
This level probe is thus insen-
sitive to ambient light (up to
50,000 lux) and suitable even
for adhesive liquids.
The conical tip of the sensor
forms an angle of 90º. This
angle acts as a prism, i.e. the
beam, emitted from the Ga-
As diode placed in one side of
the sensor head, is reflected
internally to the phototransis-
tor placed in the other side of
the sensor head (fig. 1), pro-
vided that the tip of the sensor
is situated in free air. If the
sensor tip is immersed in a
liquid, always having a refrac-
tive index different from air
(fig. 2), the beam will be
refracted into the liquid.
All types of sensors can ope-
rate in oil, waste water, aque-
ous solutions such as beer,
wine, alcohol etc. without any
kind of accessory.
Dimensions Wiring Diagrams
VP, modulated
PNP
NPN
Receiver
4 BK
2 WH
3 BU
1 BN
4 BK
2 WH
3 BU
ø14.5
17 19
ø14.5
17 19
• Plugs: Standard M 12, CONH1A-.. or CONH1O-.. series.
Accessories
VP..M.A
VP..M.A-1
ReceiverTransmitter Transmitter
Internal
reflection
Air
Refraction
into liquid
Liquid
Fig. 1 Fig. 2
