Operation Manual
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A7 MIG Welder© Kemppi Oy 2018 1824
OPERATING MANUAL
4.5 Touch sensor (seam search)
The touch sensor is a specic functional system used in
automated welding for finding workpiece’s accurate
location and position. The touch sensor hardware and I/O
are located in the robot interface unit. A welding robot
nds the particular edges of the workpiece by touching
them either with a welding wire or a gas nozzle. Touches
are detected by the touch sensor and the information is
passed on to the robot controller.
The touch sensor generates a sensing voltage separately
from the welding power source. Touch is detected when
there is a short-circuit between the workpiece and the
sensing tool resulting in a voltage drop. The negative pole
of touch sensor’s voltage source is connected to a welding
minus. The positive pole of the sensor is connected either
to a welding plus or a gas nozzle. The target for the positive
pole can be changed by a user. A relay in the touch sensor
device enables the conguration by software.
The touch sensor system consists of hardware and
software. The hardware consists of a touch sensor device, a
fast status output connector and wiring in the wire feeder’s
control cable for the gas nozzle use (see Figure 4.20 "Touch
sensing system"). The software enables conguration and
control. Conguration is available in the setup panel and
in the web user interface. The touch sensor is controlled by
the welding robot using the digital robot interface.
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Figure 4.19 Touch sensor in the robot interface unit
1. Wire feeder control cable connector (wiring for the
gas nozzle)
2. Touch sensor device inside the robot interface unit
3. Fast status output (direct hardware output)
4. Fieldbus / Digital robot interface