41
A7 MIG Welder
© Kemppi Oy 2017
1735
OPERA
TING M
ANU
AL
4.5 Touch sensor
The touch sensor is a specific functional system used in
automated welding for finding workpiece’s accurate
location and position. The touch sensor hardware and
I/O is located in the robot interface unit. A welding robot
finds 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 shortcut 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 configuration 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 configuration and
control. Configuration 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.
1
2
3
4
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
