S.p.A.
TE470/TE480 Instruction
Manual
CHAPTER 8 – INPUTS AND OUTPUTS OPERATION
Below are described the functions relative to the input and output signals on the TE470/TE480 control unit.
8.1 – FUNCTION OF THE "PRESSURE ONLY" COMMAND ("AUX" INPUT)
Usually the PRESSURE ONLY command (AUX input) is used to check, before carrying out a weld, that the
electrodes are properly positioned.
By activating the PRESSURE ONLY control (usually by pressing a push button placed on the welder handle)
while the electrodes are closing, the welder clamps the pieces to weld and waits; the operator, after having
checked the correct positioning of the electrodes, enables the cycle to continue by deactivating the control
PRESSURE ONLY (releasing the push button). If the electrodes are not correctly positioned, the operator can
cancel the operation by releasing the start of cycle device.
For welders with double stroke control only:
When the control unit is programmed to "short stroke" mode (STROKE=SHORT parameter), the PRESSURE
ONLY command can be used to move the electrodes from the "long stroke" position to the "short stroke"
position, without closing the electrodes on the workpiece. At times this operation is needed during special weld
conditions (e.g.: work on narrow thicknesses or high precision work).
The electrodes can be placed in a "long stroke" position either because they have been opened by means of the
OPEN control, or because the welder has just been switched on.
When starting the welding cycle, the TE470/TE480 brings the electrodes to "short stroke" position, thus
activating solenoid valve EV2 in 0.6 seconds. If the PRESSURE ONLY control is activated, the welding cycle
stops in this position. By keeping this condition for one second and then deactivating the cycle start control, the
electrodes stay in the "short stroke" position.
If the PRESSURE ONLY control is released, the cycle continues and the welding is accomplished.
8.2 - "SAFETY" CONTROL FUNCTION ("CHK" INPUT)
On the handle of the suspended welding gun a safety microswitch can be installed that carries out a special
function: it enables to start the cycle only if the operator has previously grasped the handle. As a rule, this
microswitch is placed in series to the start of cycle one.
In order to enhance safety, the control unit checks, through the CHK input, that the safety microswitch energizes
when a weld starts. Otherwise the TE470/TE480 does not accept the cycle start signal.
Moreover, the control unit checks that this micro-switch is neither broken (it keeps closed), nor tampered. This
test is carried out:
when switching the control unit on,
when shifting from PROGRAM to RUN
Under these conditions, the control unit displays the following error message, and it does not enable the welding
process.
PLEASE, SAFETY
RELEASE
The error does not block the machine functioning; the error will be automatically cleared, when its cause is
removed.
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