Lincoln Electric IM702-A Advanced Panel Controls, Do not USE 4-STEP if Using AN Amptrol Remote

B-5 OPERATION B-5

8.DIGITAL METER AND DISPLAY SWITCH– A 3- digit LED meter is used to monitor the preset and actual welding procedure based on the Display (momentary) switch position:

•Before welding with Display switch in center (nor- mal) position, the digital meter displays the preset welding amps set by Maximum Output control knob (See Item 6). If in Stick mode using REMOTE (See Item 5.), the digital meter displays the preset weld- ing amps set by the Remote control. (See Item 11)

•While welding with Display switch in center (normal) position, the digital meter displays the actual weld- ing amps with one amp resolution (XXX) and accu- racy within 4%+/-2A of reading.

•Any time in TIG mode and while pressing the Display switch to left, the digital meter displays the amps preset by the Minimum Output control knob (See Item 7).

•Any time in Stick mode and while pressing the Display switch to left, the digital meter displays the minimum amps rating of the machine (See Item 7).

•Any time, in either mode, while pressing the Display switch right to Volts position, the digital meter dis- plays actual output volts. Volts is displayed with 0.1 volt resolution (XX.X) and accuracy within 3%+/-1V of reading.

9.POSTFLOW TIME – This knob is used to set the TIG mode shielding gas postflow time over the range of about 2 to 60 seconds after the arc is shut off. The postflow on time status is indicated by the Green panel light.

•Gas preflow time for TIG mode is fixed at 0.5 sec- ond, with no panel control.

•Both time ranges are x2 extendable, if needed, by internal control box selection. (See Section B-7)

10.THERMAL SHUTDOWN LIGHT – This yellow LED panel light turns on if the machine output is shut- down because internal overheating has occurred, and turns off when the thermostat resets.

11.REMOTE RECEPTACLE – A 6-socket receptacle is provided for the connection of an Amptrol, or other, remote control: (See Figure B.2)

•When the Current Control Switch, (See Item 5), is in the REMOTE position the Amptrol, or other remote (10K pot), connected to the Remote recep- tacle controls the TIG or Stick mode output within the range preset by the Maximum and Minimum Output controls. (See Item 6 and Item 7, also 8 for meter display)

•When the Current Control Switch is in either LOCAL or REMOTE positions the arc start switch functions when connected to the Remote receptacle.

FIGURE B.2
REMOTE RECEPTACLE*
(Front View)
ARC START		REMOTE OUTPUT
SWITCH		CONTROL
	C	Max
	B
D		10K ohm
E	A	Min

F

*For 18-12P Plug

(LECO S12020-27)

ADVANCED PANEL CONTROLS

The following controls are included only if the Precision TIG 275 has the Advanced Control Panel (K1829-1) option installed: (Refer to Section B-10 Tig Weld Cycle Chart for graphic illustration of these TIG welding func- tions.)

12.TRIGGER SWITCH – This 2-position switch selects how the arc start switch ( connected to the above Remote receptacle) functions; in 2-Step or 4- Step mode:

CAUTION

•DO NOT USE 4-STEP IF USING AN AMPTROL REMOTE.

•Neither the arc start switch nor the output con- trol in the amptrol will function normally to shut off or control the out put. ONLY USE 2-STEP.

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•In 2-Step position the arc start switch functions the same as without the Advanced Panel:

1.Closing switch starts preflow, then a fixed (0.5 sec.) ramp time from Minimum (Start) setting level (See Item 7) to Weld setting.

2.Opening switch initiates Downslope ramp time setting (See Item 17), from Weld set- ting to Crater-fill level (See Item 7), which then stops the arc and initiates Postflow time (See Item 9).

Note: See Section B-7 for 2-Step operation during Downslope with Restart feature selected to be dis- abled, instead of enabled (as shipped).

PRECISION TIG 275