A01944 — PB/PN: sign-of-life synchronism not reached

A01944 is the alarm "PB/PN: sign-of-life synchronism not reached" — PB stands for PROFIBUS and PN for PROFINET. It appears when the bus is in the data exchange state and clock-synchronous operation has been selected using the parameterizing telegram, but synchronization with the master sign-of-life (STW2.12 ... STW2.15) cannot be completed: the sign-of-life is changing differently from the way it was configured in the Tmapc time grid. The sign-of-life comes from the master, i.e. the higher-level control system, so this is a clock-synchronization problem between converter and master rather than a condition inside the converter. The manuals for the G130, G150, S120 and S150 families describe this alarm with the same cause and the same remedy.

• The bus is in the data exchange state and clock-synchronous operation has been selected using the parameterizing telegram — this is the operating condition in which the drive expects to synchronize with the master sign-of-life.
• Synchronization with the master sign-of-life (STW2.12 ... STW2.15) could not be completed because the sign-of-life is changing differently to how it was configured in the Tmapc time grid — the master is not stepping the sign-of-life in the pattern that was configured.

1. Ensure that the master correctly increments the sign-of-life in the master application clock cycle Tmapc — if the master application does not step it as configured, correct it there.
2. Correct the interconnection of the master sign-of-life at p2045, which selects the signal source for the PB/PN clock synchronous controller sign-of-life.

• p2045 — CI: PB/PN clock synchronous controller sign-of-life signal source / PB/PN ctr SoL s_s. This is the interconnection the remedy points to: check the signal source wired here and correct it so the master sign-of-life reaches the drive as configured.

No acknowledgement is required for A01944, and the drive takes no automatic reaction when the alarm appears. The fix consists of the two remedy steps — correct incrementing of the sign-of-life in the master application clock cycle Tmapc and a correct interconnection of the master sign-of-life at p2045 — rather than of any resetting action on the converter.