Siemens F042 fault code meaning

Series: 6RA70

Tachogenerator fault

DC drive

Meaning: (Valid in operating states – –, I, II.) A check is performed every 20ms to ensure that (K0287) EMF Actual (K0179) speed Actual > +5%. The fault message is activated after 4 consecutive incorrect check results. The following rules apply: 100% Actual speed = maximum speed. 100% Actual EMF = ideal average DC voltage at α ≥ 0, i.e. with the thyristor bridge fully conducting. The ideal average DC voltage at α = 0 is π 2 3 P078.001 × ×. The monitoring function is valid only when EMF > a % π 2 3 P078.001 × ×. "a" is a percentage that can be set in parameter P357 (factory setting 10%). The monitoring function is valid only when the armature current is > 2% of the rated rectifier DC current set in r072.002. Possible fault causes: Tachogenerator or pulse encoder cable open circuit; incorrect tachogenerator or pulse encoder cable connection; pulse encoder power supply.

Possible causes

Source: 6ra70_c P426