Thesearepasseddirecttothemicroprocessorandalsototheselectiongatesoftheinterruptcon:roller. 1.4.3.3. Trigger level measurements : Whentrgerlvlisslctd,TL1 functionswitchcontactroutesinltothevoltageattenuator 7 as for voltage measurements. ContactTL3 connectstheattenuated output viatheimpedance convertortothe+ inputofthecomparator as for frequency measurements