User roles

export function IO_field_5_OnKeyDown(item, keyCode, modifiers) {

var value = parseInt(item.ProcessValue);

var HL = Tags("MV_CTRL.Output_HL").Read();

var LL = Tags("MV_CTRL.Output_LL").Read();

if (keyCode == 13) {

if (value > HL) {

value = HL;

} else if (value < LL) {

value = LL;

} else {

value = value;

}

Tags("MV_CTRL.Manual_SP").Write(value);

}

}

 My question is how can I check the role of user that is logedin and to limit input depending on that role?