Rockwell Automation 873P Programmable Ultrasonic Sensors User Manual
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Programming
These sensors will require programming using the
pushbutton at the rear of the sensor.
S
Setpoint P1 indicator is the yellow P1 LED
S
Setpoint P2 indicator is the yellow P2 LED
S
Echo/Alignment indicator is the green LED and indicates
that the sensor is receiving the proper signal from a
target.
Connector View
ECHO
LED
P2
LED
P1
LED
Set Up
Pushbutton
S
Setpoint (P1) corresponds to the 0V DC or 4mA analog
output for Pin 5.
S
Setpoint (P2) corresponds to the 10V DC or 20mA
analog output for Pin 5.
S
The analog output can be programmed with either a
positive or negative slope depending on the position of
these setpoints. For a positive slope setpoint P1 will be
closer to the sensor than setpoint P2. For a negative
slope setpoint P2 will be closer than setpoint P1.
S
See the Analog Output graphs for details.
G
Setpoint (P1)—To set P1 depress the pushbutton
until the P1 and Echo LEDs are blinking
simultaneously. (See the pushbutton set time chart for
the approximate duration the pushbutton should be
depressed).
G
Release the pushbutton for setpoint P1 programming
mode. After release, the yellow P1 LED should be
blinking slowly.
G
Place the target at the P1 position and depress the
pushbutton to program the P1 switchpoint. The output
can be set for normally open or normally closed
operation. For a normally open output depress with
the P1 LED “ON”; for a normally closed output
depress with the P1 LED “OFF.”
G
Setpoint (P2)—To set P2 depress the pushbutton
until the P2 and Echo LEDs are blinking alternately.
Note that the P1 and Echo LEDs will start blinking first
and then the P2 and Echo LED will start blinking. (See
the pushbutton set time chart for the approximate
duration the pushbutton should be depressed.)
G
Release the pushbutton for setpoint P2 programming
mode while the P2 and Echo LEDs are blinking. After
release the yellow P2 LED should be blinking slowly.
G
Place the target at the P2 position and depress the
pushbutton to set the P2 switchpoint. For a normally
open output depress with the P2 LED “ON”; for a
normally closed output depress with the P2 LED
“OFF.”
Pushbutton Set Time (Seconds)
Model
Setpoint (P1)
Setpoint (P2)
873P- DCAV1S- D5
8
12
873P- DCAC1S- D5
8
12
873P- DCAV2S- D5
17
21
873P- DCAC2S- D5
17
21
Notes:
1. You have approximately one minute to set either P1 or
P2 once you are in the programming mode. After one
minute the sensor will exit the programming mode.
2. After the setpoints have been programmed into the
sensor, they are stored in the sensor memory
(EEPROM). Loss of power will NOT cause the sensor to
lose these setpoints.
3. To change the setpoint distances after they have been
programmed requires reprogramming the sensor.
Reprogramming each set point can be done independent
of the other.
4. The setpoints can be programmed in any order.
Operation Principle
Ultrasonic sensors utilize a transducer that emits bursts of
high frequency sound waves in a cone shaped beam
pattern. These pulses are reflected or “echoed” from the
target back to the sensor and detected by the transducer.
The device determines the distance from the sensor to the
target by measuring the length of time for this echo to
return. Programmable models have three outputs. The two
discrete outputs compare this duration to that of the near
and far limits as programmed by the user via the
pushbutton. The sensor outputs are switched at these limits
based on the time duration to receive the echo. The analog
output converts the time value to a DC current or voltage
(depending on the model) that is scaled between the
switchpoints. There is an unusable area, or deadband,
directly in front of the sensor since there is a necessary
time interval between transmission and detection of the
soundwave by the transducer. This is the minimum distance
at which the target can be detected.
Sensing Distance
Bulletin 873P programmable ultrasonic sensors are
available with the following sensing ranges: 150--1500mm
and 350--3500mm. The sensing ranges are determined
using an industry standard 100mm x 100mm flat steel
target.