12 – Master(tig) 2500, 2503, 3500, 3503 MLS™/ 0311 © COPYRIGHT KEMPPI OY1. MMASelect MMA welding by pressing the selection button of MMA welding. The led is lit whenMMA is on.2. Arc forcePress the arc force button and you will see the numerical value corresponding to the MMAdynamics in the display. Factory setting for all electrode types is zero. You can change the valueby turning the pulse potentiometer. If numerical value is adjusted negative (-1...9) the arc is sof-tened, and the amount of spatter decreases when welding at the upper end of the recommendedcurrent range of the electrode. On the positive side (1...9) the arc is rough.In TIG mode, you can select the max. and min. current for the foot pedal (PEDAL LO/HI).3. Hot startWhen pressing the hot start button, you will see on the display the numerical value correspon-ding to the MMA hot start pulse. You can adjust the value by turning the potentiometer. In TIGmode you can select gas test function.4. TIG welding is selected4. Welding torch switch 2 sequence functionGas flow starts when the torch switch is pressed. After preset pre-gas time welding starts, andcurrent will rise to the welding level within the up-slope time. Release the torch switch, and thecurrent starts to drop, and after the selected down-slope time the arc is broken. After this, theshield gas will flow for the time selected.4. Welding torch switch 4 sequence functionGas flow starts when the torch switch is pressed. Release the torch switch. The ignition sparkignites the arc, and the current will rise to the welding level within the up-slope time. Press thetorch switch down, and the welding continues. Release the torch switch, and the current starts todrop and after the selected down-slope time the arc is broken. After this, the shield gas will flowfor the time selected.5. HF/contact ignition in TIG welding (water fill)TIG arc can be started either with high frequency (HF) or without (contact ignition). HF ignitionis chosen by pressing the HF CONTACT button (5) to turn on the HF light.If you use water-cooled torch you can fill it with water by pressing the HF CONTACT buttonfor more than 2 seconds.6. Remote controlIf you choose to adjust the welding current with a remote control unit you need to connect theunit and select the REMOTE button. The panel led switches off and you can select the unit(R10, wireless remote control R11T for MMA welding, or foot pedal control R11F). There isan automatic recognition of remote control units with potentiometers and only the symbol of aconnected unit can be chosen. The foot pedal control works only in 2T mode.7., 8. and 14. Adjustment of parametersTo select TIG welding parameters you only need to use two buttons: arrow-left and arrow-right.Adjustment is done with the potentiometer. When pressing the RETURN button, adjustment ofparameters goes straight to welding current. The display shows automatically numeric valuesand the units of the parameters. When you adjust the parameters, you can see the value on thenumerical display. After 10 seconds, the display will return to the welding current.