Product manual

3,%3URFHVV,QWHUIDFH%RDUG
PIB-M2001_eng.fm 55
6.15.2 Sensors
In the welding system A314/A324 containing PIB, the input for sensor 1 is con-
nected to the gas cup of the welding gun, whereas sensor input 2 is connected to
the welding nozzle for searching by way of the welding wire.
Using sensor 2 it is usually necessary to disconnect the welding circuit to avoid
current diversion through the power source resulting in too low search voltage.
Searching with sensor 2 is only used for special applications.
6.15.3 Function Description - Searching
The search of the joint is usually done using a search routine in the robot program.
The following description assumes that the ABB Flexible Automation signal
names and robot configuration apply.
In deliveries containing Smartac, programs for the search routine and configura-
tion parameters are pre-loaded. When Smartac is delivered as an option, a diskette
containing the corresponding data comes with the delivery.
Note.
The configuration parameters for Smartac usually must be modified to fit the appli-
cation in question.
In the event the configuration parameters must be modified, the same conditions
apply as for PIB. See the section Configuration.
Activating the Sensor (Sensor 1)
The sensor is activated by a message from the robot to the PIB, doSE1_SEL=1,
applying the search voltage to the gas cup of the welding gun.
The search voltage connected between the gas cup and the object to be searched is
generated by a voltage source galvanically separated from other current circuits.
Checking the Sensor (Voltage Valid Limit)
When a sensor is activated the search voltage will depend on the insulating proper-
ties of the open search circuit.
Low insulation value between the sensor and the parts having electrical contact
with the object to be searched will reduce the search voltage, due to for example
the passage of current through the water when a water-cooled welding gun is used,
soot formation, etc.
Increased contact resistance due to oxide layers, oil film, soot, etc. in combination
with decreased search voltage makes it more difficult to achieve reliable contact
between the sensor and the search object.
Using the adjustable parameter Voltage Valid Limit a level can be set under which
the search shall not continue.
Configuration range: 0 – 40 V in increments of 1V.
If the present search voltage is higher than the Voltage Valid Limit, the message
diSe_Valid=1 will be sent from the PIB to the robot giving the robot the signal for
carrying on the search.