ABB SmarTac User Manual

3.3 SmarTac board characteristics
3.3.1 Interaction with the welding equipment and weldment
SmarTac board
The SmarTac board (alone) is capable of generating a stop signal from
high-resistance surfaces with up to 1 Mom contact resistance. In real applications,
however, the SmarTac sensing circuitry is normally loaded from the surrounding
welding equipment. The electric equivalent diagram below explains the situation.
Sensitivity
Maximum sensitivity will only be obtained when using a separate, highly insulated
probe (not supplied).
Electric equivalent diagram
1
2
3
0
0
Smartac positive terminal
Smartac negative terminal
Gas nozzle (probe)
Work surface coating
Electrically conducting cooling
water or other low impedance
bridges in the welding gun, for
example, deposits from the
welding process
Open circuit impedance between
the weld power source terminals
xx1400001476
Convection-cooled welding gun
SmarTac used with a convection-cooled (air cooled) welding gun will loose some
sensitivity due to losses through the weld equipment. In the circuit above, this loss
is described by resistor #2.
Positive lead secondary contact
In systems with a positive lead secondary contact, the loss through the weld
equipment is eliminated.
Continues on next page
Application manual - SmarTac 27
3HAC024845-001 Revision: A
© Copyright 2004-2016 ABB. All rights reserved.
3 Application guide
3.3.1 Interaction with the welding equipment and weldment

ABB SmarTac Specifications

General

Brand	ABB
Model	SmarTac
Category	Accessories
Language	English