Surface Patrol
The Model 999J dual temperature sensor measures surface and ambient (air)
temperatures digitally. This system senses the pavement temperature under your
vehicle as you drive at acceptable highway speeds. The driver is alerted in
advance of temperatures that may be approaching the freezing point.
Model 999J consists of three components:
- A non-contact infrared sensor in an injection molded housing that is
mounted under the vehicle and scans the pavement as the vehicle passes over
it.
- An ambient temperature sensor that can be mounted anywhere desired on the
vehicle.
- A dashboard-mounted digital meter that displays the surface temperature as
well as ambient (air) temperature to the operator.
QTT Inc. has been producing
infrared surface temperature sensors since 1991; longer than any other company.
Our customers include Airport Operators, Cities, Counties, Municipalities and
state DOT's who are using the units to detect possible icing conditions on
runways, taxiways and highways. In doing so, they have experienced more
efficient and effective use of sand, salt and de-icing chemicals.
General Description
This motor vehicle mounted, non-contact measurement system continuously
monitors the road surface temperature to detect dangerous cold-weather driving
conditions. The electronic design of this system provides compensation for the
effects of ambient temperature changes which would otherwise result in
inaccurate measurements. The digital display output covers a surface temperature
range of -40°F to +200°F (-40°C to +90°C).
Conditions for Ice Formation
The objective of the QTT system is to continuously monitor road
surface temperatures from vehicle moving at normal highway speeds. the provides
the operator instantaneous feedback on road surface conditions and an early
alert to possible icing conditions.
The higher thermal conductivity of bridges, culverts and other similar
surface variations may freeze and subsequently thaw before surrounding road
surfaces. When ambient temperatures are near freezing, road surface temperatures
can be substantially different, presenting continuously changing driving
hazards. The new QTT 999J System alerts the driver that these
conditions exist. This dual temperature model also displays the ambient
temperature as well as the surface temperature.
Design Characteristics
The 999J Surface Patrol system is a compact instrument designed for easy
installation. The sensor head plugs directly into the meter which then provides
a digital display of the current temperatures.
Utilizing the latest in electronic and thermal technology, the rugged and
compact sensing head converts heat-generated infrared energy into electrical
signals which are then translated into calibrated temperature information which
is then displayed.
Installation
Mechanical installation requires mounting the sensor on the underside of the
vehicle. The sensor includes a conical mounting and adjustment assembly to
protect the sensor from dirt, water, road debris and vehicle vibration. The
meter powers the sensor and requires 12 or 24 volts D.C.
Operation & Maintenance
To operate, simply switch on the vehicle ignition and the system is
operational. Maintenance is limited to periodic cleaning of the optical lens
within the sensor housing. The frequency of this maintenance is dependent on the
operational environment. To clean the lens, unscrew the tube on the bottom of
the vehicle-mounted sensor housing and wipe with a tissue dampened with a lens cleaning
solution then wipe dry.
Specifications
| Sensor
Assembly |
Injection molded housing
with lens protective cone |
| |
Accuracy |
±0.5°F for operating ambient temperatures from 0-120°F
|
| |
Repeatability |
±0.1% of full scale |
| |
Shock |
50 G's |
| |
Vibration |
10 G's in any axis |
| |
Response time |
80 milliseconds to 95% of final reading |
| |
RF Hardening |
Withstands external radio frequency effects caused by
mobile radios |
| |
Maximum measurement region |
1 inch (2.54cm) O.D. |
| |
Operating Ambient Temperature |
-40°F to +160°F (-40°C to 70°C) |
| |
Supply Voltage |
12 or 24 VDC ±25%, 150mA max |
| |
Optics |
Precision Germanium Crystal |
| |
Weight |
Sensor alone: 2oz (60g) |
| |
w/cables & connectors: 10oz (280g) |
| Meter
Assembly |
High brightness red LEDs. Displays both
Surface & Ambient temperatures in Fahrenheit or Celsius |
| |
Field calibration |
Adjustable ±5°F over ice |
| |
Weight |
4.5 oz (128 g) |
| Meter
Options |
Analog or Serial Output |
| |
Analog Output Modes |
Voltage or Current loop |
| |
Analog Voltage Range |
1.00-5.00V, isolated. User programmable gain and
offset |
| |
Analog Current Loop |
4.00-20.00mA, isolated. User programmable gain and offset. |
| |
Loop power |
Internal (isolated) or external |
| |
Serial Output |
EIA/RS-232C, 300-9600bps |
| General |
|
| |
Electrical Connections |
Compression terminals for input voltage |
| |
Quick disconnect watertight circular system connector |
| |
Data Standards |
SAE J1708 and J1587 |
| |
Cable Length |
18 feet (8.5 m) standard |
Long-term accuracy not to be affected by harsh winter weather conditions
including severe splashing of snow, slush, mud and water.
|