Banner U-GAGE T30UX Ultrasonic Sensors - Manual (Page 2)

Overview
The U-GAGE® T30UX is an easy-to-use ultrasonic sensor with extended range and
built-in temperature compensation. Simple push button configuration provides flexibili-
ty for a variety of applications.
Easy-to-see indicator LEDs communicate the status of the sensor. The Green “Pow-
er” LED ON indicates that the sensor is in Run Mode (the sensor’s normal operating
condition). The Red “Signal” LED indicates the target signal strength. The Amber
“Output” LED indicates that the output is enabled and the sensor is receiving a signal
within the window limits (depending on NO or NC). The Amber “Mode” LED indicates
the currently selected mode.
Power ON/OFF
LED (Green)
Discrete Output
LED (Amber)
Signal Strength
LED (Red)
Mode LEDs
(Amber)
Figure 1. Features
Principles of Operation
Ultrasonic sensors emit one or multiple pulses of ultrasonic energy, which travel through the air at the speed of sound. A portion of this
energy reflects off the target and travels back to the sensor. The sensor measures the total time required for the energy to reach the
target and return to the sensor. The distance to the object is then calculated using the following formula: D = ct ÷ 2
D = distance from the sensor to the target
c = speed of sound in air
t = transit time for the ultrasonic pulse
To improve accuracy, an ultrasonic sensor may average the results of several pulses before outputting a new value.
Temperature Effects
The speed of sound is dependent upon the composition, pressure and temperature of the gas in which it is traveling. For most ultrasonic
applications, the composition and pressure of the gas are relatively fixed, while the temperature may fluctuate.
In air, the speed of sound varies with temperature according to the following approximation:
In metric units: C
m/s
= 20 √273 + T
C
In English units:
ft/s
= 49 √460 + T
F
C
C
m/s
= speed of sound in meters per second C
ft/s
= speed of sound in feet per second
T
C
= temperature in °C T
F
= temperature in °F
Temperature Compensation
Changes in air temperature affect the speed of sound, which in turn affects the total time for the echo measured by the sensor. An
increase in air temperature shifts both sensing window limits closer to the sensor. Conversely, a decrease in air temperature shifts both
limits farther away from the sensor. This shift is approximately 3.5% of the limit distance for a 20° C change in temperature.
The T30UX series ultrasonic sensors are temperature compensated. This reduces the error due to temperature by about 90%. The sen-
sor will maintain its window limits to within 2.2% over the -40° to +70° C (−40° to +158° F) operating range of the sensor.
NOTE:
• Exposure to direct sunlight can affect the sensor’s ability to accurately compensate for changes in tem-
perature.
• If the sensor is measuring across a temperature gradient, the compensation will be less effective.
Sensor Configuration
Two TEACH methods may be used to configure the sensor:
• Teach individual minimum and maximum limits, or
• Use Auto-Window feature to center a sensing window around the taught position.
U-GAGE® T30UX Series with Discrete Output
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