I'm starting to have a play with the sub-menu on the Lorch HandyTig HT200 and am comfortable with most of the parameters and their adjustments (AC and pulse frequency, balance, upslope/downslope etc.) but am not sure what the following does: Plus Pole Current Correction (code 11P in the menu) - the description in the manual is "Ignition using the positive terminal is used for optimum dome formation in TIG AC welding. This positive terminal current is preset in the unit and can be increased or reduced by the quoted percentage." and has an adjustment range of 10% to 200%. I understand the % setting to be the % of the welding current but the bit about the positive terminal doesn't make sense to me. Playing around with different settings doesn't seem to make any or much difference. Can anyone give some guidance on this and when adjustments are needed? I'm quite happy to leave it as is because I've found all the default settings to be spot on but I would like to understand the machine settings and capabilities better. Also, Is this something unique to Lorch or is it something that is common but named differntly on other machines?